I read a story one time about a mysterious player who visited the casino one time per month. He would look at the table for many spins, make a single bet, win a small amount and leave. When he entered security was on high alert, they all had their eyes on the monitors, didn't see anything suspicious. When he left they would pull up the footage from his previous visits and examine it again. They did that every month and thought it was hilarious how he came to "steal" something like 50 bucks one time per month and got away with it every time.