My John Deere rider mower has a button on the dash if you want to keep the blades turning in reverse, you simply push it and the engine keeps running.
If I lean over to pick up something that might get wound up in the blades the engine stops, so I pull the plug under the seat, put it neutral and it keeps running.
Bobert is right, those "Safety switches" are for people who shouldn't be running machinery anyway. :-)