Last summer I went to my local mega mall to do some focus testing on a big telephoto lens. 10 am on quiet weekday. I pulled into a large empty area of the parking lot and set up my camera on tripod to shoot store fronts, signs, and brick walls 100 to 200 yards away.
Suddenly I was attacked by mall security from three directions at once. First rent-a-cop approached, the other 2 triangulated me. No guns drawn, but hands on holsters. A brief conversation ensued. Someone had reported a man with gun! I was allowed to continue, but one guard remained close by until I left.