Don't think that a gun in the Petit situation would have changed much as they did not seem to have the "survival" mind set.
What happened got a lot of people to thinking and firearms were sold as a "feel good" measure.
People have to change their Thinking, just having a handgun alone will not be enough.
They have to have the mindset to USE the firearm and to become proficient in it's use.
Best example is Wm Shatner as Denny Crane in "Boston Legal" whenhe drops the mugger in the parking garage.
Then says, "America, Land of Liberty Valance". A n old movie starring John Wayne, Jimmy Stewart and Lee Marvin
http://en.wikipedia.org/wiki/The_Man_Who_Shot_Liberty_Valance
I was typing a reply to that effect, but got frustrated by this crappy keyboard and quit. The most important part of armed self defense is, in this noob's opinion, mindset. The Marine Corps Rules of Gunfighting are good for a chuckle, but one of them I really do take to heart: "Decide to be aggressive
enough, quickly
enough." I think a lot of people miss that point. It's not nice, it's not clean, or fun, or anything; at some point in an encounter like the Petits, the good guy has to A) recognize, and B) come to terms with, the fact that
somebody is going to be very seriously injured or possibly killed. I really think a lot of people aren't able to fully embrace that concept; so even if they have a gun, they're pulling it out and pointing it at the bad guy in the hopes that this can somehow still come to an agreeable conclusion for all involved. It can't. Embrace the suck; somebody isn't walking out of this house. I don't like it, I wish you hadn't come here, I wish you hadn't chosen
me, I wish, I wish, I wish... But you did, and when it comes down to it, friend, it won't be me or mine on the gurney, not today, not if I can help it.