Used to be, may still be, in Oklahoma it is against the law to carry in businesses that post a "no firearms allowed declaration".
Good thing back a couple of years ago, no penalty for the law. Just a law...suppose they could get you for trespass, but the cops could come, bring you in if they felt like it, book you, then after all the paperwork it was away to the house.
If there are some other Okies here, maybe you can let me know if it's still that-a-way.