He means that some people think the key stays in the "start" position rather than "ON"
there's no motor for the key or anything like that. If the vehicle is in motion, turning it back to the "on" position will do exactly as you have described- just make it back to normal.
My point is, it still had to have been bumped. Do you have a lot of keys on a keychain?
Otherwise I may suggest an exorcist.