Why ? Because i have no interest in having my property searched by a private company with no cause, They have no legal right to detain or search me unless they believe that i have stolen something by stoping and asking me for my recipt on the basis that i do not have my items in bags is simply that an detainment and accusation of theft.

what do you stand to gain ? I gain nothing, But i dont lose anything ether, Consenting to a search on the basis that other people might be staling is just bullshit. If they choose to trespass me thats on them, Good luck with that, Im not standing around having a conversation, To be trespassing i must be on their property after they have told me to leave, If they are detaining me then obviously im not trespassing.

It's a fact businesses will lose more money to INTERNAL THEFT to shoplifting.

I don't have to prove I'm not a thief in order to walk through your store.  I'm no lawyer but it'd be pretty hard for a business to trespass you just for this.  There's this document, maybe you've heard of it Eyeeatingfish, called the Bill of Rights written a long time ago that provides us protection against illegal searches. 

The other day I went to WM to pick up one item I needed. I had a lot on my mind and was in a hurry. On my way out the guy at the door said something to me. I am also hard of hearing and said "you too" as I walked out as I thought he might have said have a good day. But in after thought he could have said can I see your receipt. I really don't know. I don't care either. However, if I had heard him ask for my receipt I would have shown it to him. 

Just speculating here but I am pretty sure that is a safety issue. All it takes is one idiot to spill something that causes another person to slip and fall and Costco is faced with a lawsuit for hundreds of thousands of dollars. Not that they think you are that idiot but they never know and cannot predict it thus have to enforce it evenly.

Buzzzzz!!!! - Wrong again.   If they were concerned with slip and fall cases....why would they hand out food and drink samples INSIDE?!!!!  The real reason why they make you get rid of your outside food is so you'll spend more at Costco. 

Buzzzzz!!!! - Wrong again.   If they were concerned with slip and fall cases....why would they hand out food and drink samples INSIDE?!!!!  The real reason why they make you get rid of your outside food is so you'll spend more at Costco.

Exactly! It's all about the all mighty dollar. Nothing wrong with that in my opinion. To think anything else is to not understand reality. JMHO

I never show my receipts. It has got me followed to my car, yelled at, sworn at and threaten with the police being called.

Haha maybe it's guys like you who cause stress for the security guards at Don Quijote! They mentioned to me once that they were having a really bad day with fights at the exits.

I haven't had any complaint with showing my receipts so far. After you do it once or twice, many guards will remember you and they'll never ask you again. Even when they do check, I've never had someone look through my stuff. They just glance at the receipt and check it off.

Most grocery stores do have their checkouts near the exits. Times has the one-way stalls, though I've crouched under the rails without incident.

Airports on the other hand, I have a lot of complaints. Doesn't matter anymore, as heightened security applies to almost everyone now. But back when it was only starting, I was always the one guy they'd stop and make me take my shoes off. Once they thought my Sega Dreamcast was a bomb, called security, and made me empty my bags onto the floor right in the open. They even made me open my Dreamcast box and show them all my games one by one.

Shop Amazon. No need to show receipt 

I don't have to prove I'm not a thief in order to walk through your store.  I'm no lawyer but it'd be pretty hard for a business to trespass you just for this.  There's this document, maybe you've heard of it Eyeeatingfish, called the Bill of Rights written a long time ago that provides us protection against illegal searches.

IANAL, but I'm pretty sure if you're on private property (like Costco) they can trespass you for just about anything...  Also pretty sure the Fourth Amendment protects us from unreasonable search by agents of the government (e.g., cops).  I expect you could refuse to let Costco search you on the way out and they would have no right to detain you without probable cause to believe that you'd been shoplifting, but in that case they could banish you (in which case any future visits would be criminal trespassing) and I don't think there'd be a whole lot you could do about it.

Buzzzzz!!!! - Wrong again.   If they were concerned with slip and fall cases....why would they hand out food and drink samples INSIDE?!!!!  The real reason why they make you get rid of your outside food is so you'll spend more at Costco.

Agree to disagree. I mean, sure increased sales can be a side benefit, but spills is still absolutely a concern. Many clothing stores do not allow food and drinks into their stores but they are not selling food or drink so they clearly do it for reasons other than spending more money.

The receipt check at Costco doesn't seem effective when all the person does 90% of the time is glance at the receipt, glance at the cart, scribble and then I leave.  Based on quick glances how is he supposed to find the extra bottle of liquor or see that I was charged twice for granola bars.  It's a joke.

Have you ever tried asking one what they look for? I did, and he said that they look at the number of items and I think he said something about the big ticket items. There is no way to check every item, but if there is a TV in the cart it would be easy to scan the receipt for the TV

IANAL, but I'm pretty sure if you're on private property (like Costco) they can trespass you for just about anything...  Also pretty sure the Fourth Amendment protects us from unreasonable search by agents of the government (e.g., cops).  I expect you could refuse to let Costco search you on the way out and they would have no right to detain you without probable cause to believe that you'd been shoplifting, but in that case they could banish you (in which case any future visits would be criminal trespassing) and I don't think there'd be a whole lot you could do about it.

Precisely.

Additionally, if the store security did suspect you of shoplifting and detained you, they can actually get away with looking in your bags before the police arrive because they are not agents of the government and not restricted by the 4th amendment.

IANAL, but I'm pretty sure if you're on private property (like Costco) they can trespass you for just about anything...  Also pretty sure the Fourth Amendment protects us from unreasonable search by agents of the government (e.g., cops).  I expect you could refuse to let Costco search you on the way out and they would have no right to detain you without probable cause to believe that you'd been shoplifting, but in that case they could banish you (in which case any future visits would be criminal trespassing) and I don't think there'd be a whole lot you could do about it.

Costco is a different animal because you have paid membership and agreement with them. 

Precisely.

Additionally, if the store security did suspect you of shoplifting and detained you, they can actually get away with looking in your bags before the police arrive because they are not agents of the government and not restricted by the 4th amendment.

Bzzzzz! - Wrong again.  There are legal elements that store security must satisfy in order for them to even stop you - let alone call the cops to have you arrested or tresspassed.

Bzzzzz! - Wrong again.  There are legal elements that store security must satisfy in order for them to even stop you - let alone call the cops to have you arrested or tresspassed.

Sorry...  Any private property owner can trespass you for almost any reason.  Ever see the "We reserve the right to refuse service to anyone" signs?  "No shirt, no shoes, no service" signs?  With very few exceptions, if you are asked to leave and you remain, or return to a place from which you have been barred, you are guilty of trespassing.  Doesn't matter if it's a membership club like Costco or a variety store like Target.

Bzzzzz! - Wrong again.  There are legal elements that store security must satisfy in order for them to even stop you - let alone call the cops to have you arrested or tresspassed.

I was only talking about what they can do if they stop you. So I was not wrong, I was not addressing the legal elements needed to detain someone. Different issue.

Sorry...  Any private property owner can trespass you for almost any reason.  Ever see the "We reserve the right to refuse service to anyone" signs?  "No shirt, no shoes, no service" signs?  With very few exceptions, if you are asked to leave and you remain, or return to a place from which you have been barred, you are guilty of trespassing.  Doesn't matter if it's a membership club like Costco or a variety store like Target.

Correct, the only time they cannot trespass warn you is if it has to do with a person being a protected class meaning they cannot trespass you because of race, religion, sex, etc. They can trespass you if you are ugly or like the wrong sports team though.

No quotes because that would take forever.

Costco and Sams are the only 2 places i stop and thats because its a members store and as such i have agreed to that with my membership.

You can not be trespassed from a store for not showing your receipt, Trespassing is a criminal act and requires a person to remain on the property after being given reasonable notice  to leave (or crosses into an enclosed area designed to exclude intruders)
Even if you are told verbally by a security guard not to come back no more ect....... this is not a legal reasonable notification. You would need to be told in Writing that you are not allowed on the property.

You can not be trespassed for another reason then staying on the property AFTER you have been notified by an AUTHORIZED agent to leave,

No quotes because that would take forever.

Costco and Sams are the only 2 places i stop and thats because its a members store and as such i have agreed to that with my membership.

You can not be trespassed from a store for not showing your receipt, Trespassing is a criminal act and requires a person to remain on the property after being given reasonable notice  to leave (or crosses into an enclosed area designed to exclude intruders)
Even if you are told verbally by a security guard not to come back no more ect....... this is not a legal reasonable notification. You would need to be told in Writing that you are not allowed on the property.

You can not be trespassed for another reason then staying on the property AFTER you have been notified by an AUTHORIZED agent to leave,

Being trespassed means you are given an order to leave and not return. From that point on, you will be committing trespassing if you return and you can be arrested for it. And they can trespass you for any reason other than for protected class reasons. That means that they can trespass you for refusing to show a receipt. If I go into a bank and refuse to remove my hat and sunglasses they can trespass me. Someone can trespass me from their club if they say I am too ugly. A trespass warning is not contingent on a criminal act.

You are correct that the warning is supposed to be communicated in writing, but when it comes down to it, how do you think it would play out in court if arrested for trespass? Is your defense going to be that they never notified you in writing? If they say that you refused to sign it do you think that is going to mean the trespass warning is not valid? Now if an employee simply told someone "brah, no come back" then that would not suffice, but a simple lack of cooperation would not invalidate a written trespass warning. I just don't want anyone to have the false impression that as long as they refuse to sign a trespass warning they cannot be arrested for violating the trespass warning.

So far my instinct tells me eyeeatingfish is probably correct on his understand of trespassing. But I am not sure I believe him on the detaining and searching issues. When strangers come into my yard to steal stuff the police always ask me if I want to trespass them. But I wonder if I am legally allowed to detain them forcefully, or even search them forcefully?

they can't detain you for not showing your receipt - in other words they can't stop you from leaving the store for something you paid for already. There's no sense for a store to issue a trespass violation to a customer that has paid for an item.
When I'm done waiting in a 6 people deep line to pay for something I'm like Ludacris.
Like I said, maybe they should position cashiers closer to the exit rather than having another layer of items for sale AFTER you pay for something. That's one way to separate those customers who have paid and are exiting the store from those who are still shopping.

Being trespassed means you are given an order to leave and not return. From that point on, you will be committing trespassing if you return and you can be arrested for it. And they can trespass you for any reason other than for protected class reasons. That means that they can trespass you for refusing to show a receipt. If I go into a bank and refuse to remove my hat and sunglasses they can trespass me. Someone can trespass me from their club if they say I am too ugly. A trespass warning is not contingent on a criminal act.

You are correct that the warning is supposed to be communicated in writing, but when it comes down to it, how do you think it would play out in court if arrested for trespass? Is your defense going to be that they never notified you in writing? If they say that you refused to sign it do you think that is going to mean the trespass warning is not valid? Now if an employee simply told someone "brah, no come back" then that would not suffice, but a simple lack of cooperation would not invalidate a written trespass warning. I just don't want anyone to have the false impression that as long as they refuse to sign a trespass warning they cannot be arrested for violating the trespass warning.

The warning is not "supposed to be communicated in writing" It is required BY LAW to be in writing. This is how it would be played out in court (i doubt it would even get to court), Your honor i was not aware that i was trespassing as the area was open to the public and no written notification was  provided to me as per HRS  708-814.
I dont know where you get the signing part from, You are not required to sign any trespass notification, Just being present with it is enough. 

The fact that you are leaving the store when you are asked for your receipt means you cant be trespassed anyway, as to be trespassing you have to be on the property after being asked to leave.

Trespassing is the criminal act itself, To be trespassing you have to of refused a request to leave. If you walk into a bank with sunglasses on and they ask you to take them off that does not mean that they can trespass you. If they ask you to take them off and you say no, then they say can you leave then and you say no, then they can have you trespassed.