I don't see the harm in starting a four player game or leaving in the middle of a game. It's tough to watch little kids who have no idea what they are doing just beat on the flippers. However, I don't want to be the cranky get off my lawn guy. Beat away. I don't exactly baby my machines when I play them either. It's great when kids get excited seeing my pins. Sad thing is few really seem to get into it. Maybe I need more pins. lol