Good post. Yes, I have seen this, and I always either have a firm grip on the prop or else my body parts out of the way when I hit the switch. Under just the right conditions, the engine could actually start all by itself.

The old Ford Model T cars had what they called buzz coils that provided the spark as soon as you turned the ignition on. My father said he had a one that quite often would fire up and run when the key was turned on without even cranking the engine over. (Usually after the engine had been recently run and then shut down.)

AV8TOR