Tilt penalty: game over.

http://www.ipdb.org/machine.cgi?id=1262

I think games that have the ball serve plunger are usually game over. That's not "all EMs" of course so your question is a little off. EMs without that mech usually aren;t game overs. Sure there are exceptions over time though.
Enjoy!

some games have a single jones plug for tilt in/out
you can have the game end on tilt or just the ball

The game over penalty is a bit rough, but hey you can just push all the balls in play at the same time for some early free multiball action!
of course the scoring doesn't really work that way

Indeed. Because of the way EMs work they cant process more than one scoring at a time, like 2 targets at the same time, so that's why it doesn't really pay to shoot a couple at the same time...although it's fun.