There's a sign next to the front door that says we ban guns. However, the way the laws are written in Minnesota, you can't actually get in trouble for bringing a concealed weapon into a business with a sign like that - all they can do is ask you to leave. You can only get a fine if you refuse.
Of course, there's no law saying my company can't fire me for bringing in a gun... they probably would. Not that I feel the need to bring one, and I don't even own one anymore.
The more ardent pro-gun folks around here sometimes seem to make a habit of going to no-guns-allowed facilities (such as the Mall of America) with a concealed weapon anyway. I don't know if it's because they want to "express their freedom" or just test the limits of mall security. Hell, a few of them could be hoping to get caught and subsequently mistreated so they can sue, although I'm sure if anyone does do that they are in a tiny minority. Some people may also do it just to expose the MoA's security as the joke that it is. I don't know.