Well, back when I was in my late teens, I used to have this friend that enjoyed playing pool but didn't enjoy the games we would play so he would get his own table while I played and usually left way before I did. His favorite quote leaving the college student union was "table 3 said he was going to take care of my time", well it wasn't always "table 3", it was whatever table I was playing on. The dam guy was trying to ditch his bill on me and it worked more than a few times because there was always a different college student working behind the counter.
I confronted him the very next time I saw him and he payed me back for the time and it was sorta a joke between us from there on out because he kept doing to see if he could get away with it. It was fun for me too because I used to flip the person working the counter a hard time because I would always act surprised when I heard I had his bill to pay for.
Thinking back on it, I should have had the police called on him, now that would have been funny to see.