Most "gun free zones" aren't legally enforceable. They're house rules put in place by the businesses. It's not a criminal violation to bring a firearm into one.
If the business owner realizes you're armed, they may ask you to leave, and you're best advised to do so, refusal at that point puts you in a position where you're trespassing which IS a criminal violation.
There are very few statutory defined places you can't bring a firearm. Courthouses, federal property, schools, etc.
Movie theaters with signs, Malls, etc... that's almost always a corporate policy not a law. Concealed is concealed and if you get burned and you're asked to leave, be an adult and leave. Next time pay better attention to the signage so you don't have a similar misunderstanding in the future.