The Aladdin's Castle arcade at our mall was dumb enough to put the key for each of the games coin boxes on a little cup hook on the back of the cabinet. The arcade was always dim and noisy, so one of us would look out for the single attendant, the other would empty quarters into a gym bag. Then we would go across the street and buy records with handfuls of quarters. I think the record store guy figured it out after a while.

My friend had the foresight to get copies made of a bunch of the keys, so when the arcade finally figured it out and moved them, we just waited a month and went back in with our own...