I believe that going back and forth through the metal detector is a way of resetting it. It's done at the beginning and end of shifts.
As far as the rapper, I complained once about a young man who did it when ever he was unoccupied. I told the supervisor it was very unprofessional, and all I got back was he didn't do it when he was on the line, only at the exit. But still.........


airlinebrat53