Oakview mall in Omaha has a sign on one of the doors at main entrance, it's been about a year since the last time I was there, don't remember a sign the last time.
After the long walk back to lock my gun up, I was put at ease by the large amount of mall cops with radios, knowing if there was an issue they could call someone with a gun. (sarcasm)
I see they are already on the naughty list.