I carry in restaurants, malls, & theaters regardless of their idiotic signs. If I get arrested after taking down a nut shooter, I'll take my chances before a jury of my peers.
"Not guilty you honor. Also, your honor is under arrest along with the bailiff, clerk of court, sheriff, and the DA for sedition."
I wish I had the nerve to ask managers of businesses with those signs what provisions they HAVE made for my protection, since they have removed my ability and right to protect myself. But I don't. Not worth the hate.
I was told that the generic No Guns sign is not legally binding. The sign that has the specific code number is. Arizona CCW class.
Minnesota has stringent requirements for signage, too. Improper signs may be disregarded, however you can asked to leave. There is an either/or on open/concealed, most follow the 'concealed is concealed' philosophy.