I asked three casino executives about this hypothetical situation. They all said that you can’t win a bet if you don’t make a bet. In the case where betting somebody else’s money is consensual then they will pay the person pressing the buttons. However in the case where it is not consensual they will not pay the person who pressed the button. A more difficult question is whether they will pay the person who did put money in the machine. That seems to be taken on a case by case basis. Considerations include whether the player was vigilant in guarding his machine, how much the player was playing for, and if he is a known good customer. Basically a player should follow the McDonald’s rule of "keep an eye on your fries." However even if the player was remiss in guarding his machine the casino may not want to anger a good customer. It also helps to be playing a high denomination game.