What happened here?

Was out at the fair grounds the other day when they were pulling all the rides down and I asked the front office if it would be all right to hunt the grounds and she said fine but not right now. I said how about the parking area? she said go ahead. I spent probably four hours out in that grassy area and moved over and ended up at a spot close to one of the openings in the fence when my detector [Safari] goes nuts. I do not seem to be able to swing it at all without it screaming at me. I move around some and it just won't shut up. I raise it in the air and it stops, lower it down and it just won't shut up. Well I'm groaning to myself thinking it is busted and decide to go over to the area where I was a little while ago and try it there. I start to leave and I realize those are all good signals. I move back over and start at the edge and start digging. everything is about two inches down. In about a ten foot area I pull out around $6 bucks. All quarters dimes and I think about three nickels and a couple of penny's. What in the world happened here?? Someone just take the cash box and throw in in the air then pick up the paper and leave? I went back later and found two more quarters and a dime. What do you think happened here?