There is some mysterious Joker who is getting me irritated over the last two-three years. He /she will come into my Mat and take my out of order sign from a bad machine, then stick it on a good machine. Of course, this causes more hassle because then someone else will use the out of order machine. Then, more recently, I and my attendants wrote the machine number on the card, so I can see if someone switched it to another machine. So the Joker gets wise and instead of switching the card to another machine, he just tosses the card altogether. I have a camera system, but don't want to spend my free time wasted on this issue. Any suggestions ?