Easy, don't patronize their establishments.Thanks for the post, and this is unfortunate. Basically what this means is, the kid from Columbus should have left his gun in the car, and Greenwood mall should have relied on "quality control sampling" from a dood with a dogg to stop that shooting.
Just wait until the cost of electronic gun detection systems comes down to less than what it costs to train and pay canines and their handlers. Concealed Carry America is going to get a Red Pill.
I can't recall the last time I've been to a mall, even though that bourbon chicken at the food court is tempting.
No gun signs don't carry the force of law, so as long as it's not a prohibited place, carry on!