Quoted from Crash:
I help my dad run machines at his laundromat and every so often we will give free credits to the local kids. I put 3 credits on a machine and he presses the start button a million times and burns up all his plays at once. Afterwards he comes back to me wondering where his games went.
Some machines beg for multiplayer even when playing alone. For example its the only way to get a Special on BK.