Slam tilt switch is optional on newer Sterns. If you enabled that you can wire a leaf switch so when you press a coin return the game slam tilts and resets.
In home environment coin mechs aren't used so only you would know it's there.
F'n annoying when people walk off and leaves balls in shooter lane or 4 player games running. One of my biggest pet peeves. People do it all the time at work when looking at machines.