Let's start here: An establishment (not Federal building, or other public building where concealed carry is prohibited) has posted on the door that firearms are prohibited, even by those who are licensed to carry. If you carry concealed into the establishment, they wouldn't (or shouldn't) know, right? If for some reason, it was discovered that someone was carrying in that establishment, what would be the consequences? What could the establishment do, other than request that you leave or call the police? I can't seem to find anything.