For what it's worth, there actually are kill switches on the sides of the ICE buses that service my university campus. Opening the little hatch and pushing the button disconnects power from the battery and kills the engine.

I imagine it's useful in situations where the engine has caught fire and you need to stop fuel flow ASAP. I've never heard of people abusing it, probably because everyone on board the bus including the driver could easily ID the wrongdoer. Of course, private personal vehicles are a different story.