I had a shitty retail job for a summer in college. It was one of the first things we were told and it was the late 90s. Let them shoplift. Don't say anything to them. Tell a manager who also wouldn't do anything but photograph them. We were encouraged to make them uncomfortable by following them around but this was a store 30 mins from Philly. It was an okay area but the shoplifters mostly took the bus from Philly. I stayed far away from anyone who didn't look like they belonged in an office supply store.