Interesting read. In Minnesota, landlords cannot ban guns. So, each leased store has to be posted in order to ban guns. Malls can't ban permit holders from carrying there. Now, some malls up here do have signs, but they are never posted properly. The mall I frequent has on sign on each entrance on the side wall as you come in. You really have to look for it. Funny thing is there's a Dicks Sporting Goods store in the mall now and they sell guns None of the anchor stores have the signs.
The Mall of America had the signs prominently posted when our law was passed, but slowly but surely they have taken them down or put them in spots less noticiable. Now Bass Pro is coming to that mall, so I kind of wonder how they'll ban guns there.
By the way, the signs here are basically meaningless. If you get caught with a gun, the owner has to tell you to leave, and if you don't, then you get a $25 trespassing ticket.