Stern Playboy - got stuck in some never ending loop of ball saves and it just wouldn't end. Tilted to end ball 1 and then plunged balls 2 & 3 just so I could put my initials in.
As for people walking away mid game, that's why I always have my machines set to 'instant restart' when I take them to shows and they are out for public use. Nothing worse than having to plunge up to a dozen balls just so you can start a game, especially when there's a lengthy ball save set up.