Dallas TX no guns sign have the force of law. You'll get arrested if you go into a store with a no guns sign.
Depends on what you mean my "no gun sign". In TX if a business does not want to allow concealed/open carriers they must display Texas Statue 30.06 (no pun intended) for conceal carry, and/or 30.07 for open carry in a conspicuous manner with minimum 1 1/2" tall lettering. Normally they are printed on the doors of the business.
"“PURSUANT TO SECTION 30.06, PENAL
CODE (TRESPASS BY LICENSE
HOLDER WITH A CONCEALED
HANDGUN), A PERSON LICENSED
UNDER SUBCHAPTER H, CHAPTER 411,
GOVERNMENT CODE (HANDGUN LICENSING
LAW), MAY NOT ENTER THIS PROPERTY WITH
A CONCEALED HANDGUN” "
"“PURSUANT TO SECTION 30.07, PENAL
CODE (TRESPASS BY LICENSE
HOLDER WITH AN OPENLY CARRIED
HANDGUN), A PERSON LICENSED
UNDER SUBCHAPTER H, CHAPTER 411,
GOVERNMENT CODE (HANDGUN LICENSING
LAW), MAY NOT ENTER THIS PROPERTY WITH
A HANDGUN THAT IS CARRIED OPENLY”
The little gun-buster sticker(alone) on a door doesn't count.