True Dick, very true. I always thought a very if not most imporant part of autorotational training whether throttle is chopped or slowly wound off, happens at the point after the collective has been lowered and aircraft stabilised with the judgement by the check pilot which is confirmed by the words and action, - "Safe to reach an area, throttle in over ride check."
I only chop the throttle on a most recalcitrant subject who has been too dim to work out - or more likely was not trained properly - in the why / how that thaing on the side must be gotten down. Or first when I am checking that the carburettor is set properly and will not cause the engine to stop at throttle chop while the aircraft is still firmly attached to the ground.
At all other times it should be a gentle wind off, especially when checking the free wheel, as the more gentle you do it, the more it proves to you it will work when the engine suddenly stops. That's my simple logic any rate.
deliberately cutting the engine could lead to hard questions from the insurer.