I've worked on old EM's that get stuck in a reset cycle where something just isn't quite right and every time the score motor made a revolution it added 1 to the total play meter. I know I've had some click a few hundred times while testing or looking for a problem and no ball has touched the playfield.

Who know how many times a game has been stuck in a reset cycle and not been played. Some people just leave them on and stare at them trying to fix them for a long time. I'd rather get a total coin number and maybe add 5-10% for free games