Casinos really shouldn't be sending a lot of promotional dollars to penny players, but they do, it's probably the biggest "advantage play" going on right now. Casinos think the penny players are playing the tightest machines, which is true, but by law they can't be tighter than 15% hold, assuming gaming control is checking. The problem is penny players put in hardly any coin in, maybe a dollar per hour, and 15% of a dollar is 15 cents. If the casinos give the penny players more than that, it's an overlay ("advantage play") for the players. Just the power bill alone on a modern slot is probably over that.
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