One late evening in Thailand I got on a hotel elevator and a man in a suit got on behind me. He punched a floor number higher than mine, but got off with me on my floor, where he claimed to be security. He stated that he believed I had an unregistered guest in my room and insisted on looking in. So I let him, where he found no one.
When I brought it up with management the next day, they said they would check into it. Their response later was that no one in security had reported doing anything like that. On top of that, the description I gave of the guy's clothing did not match the clothing worn by their security. I still wonder who he was and why he didn't see me escort my guest out right before I got on the elevator.