Hey Scoob, per the ops manual, the only person that can turn off the engine is the CFI as PIC in the aircraft, he better be damn sure that he can recover any situation after dead sticking it as he is not only answerable to the family, RA Aus,and the insurance company if it goes pear shaped, but he will have to ask himself what actual benefit he was trying to show from the exercise. While it certainly adds "reality " to the exercise, and may show the true glide characteristics of the aircraft. I feel more time catching pilots out just by pulling the throttle when they least expect it or, waiting till they are miles out in circuit, sure sorts them out and teaches more valuable lessons about positioning and situational awareness.
I'm sure there will be numerous other views on this subject, but dead sticking is something glider pilots do all the time, go fly a few hours in them if you want quet with your aviation experience, otherwise you might as well just turn the mags off as you roll up to the hangar!