I figured out the deception of well rehearsed martial arts demonstrations when I was about eight. Well...ok...when I was about twelve.
I forget the name of the dude who used to train with Bruce Lee. When he was younger, he once went to a Kung Fu demonstration where some very well known Ultra Kung Fu Master was giving an awe-inspiring demonstration that had the crowd captivated, many of whom were martial arts enthusiasts. Made his way to the front, shouted that it was all bullshit, walked up on stage and told the Kung Fu Master to try those moves on him. Then he actually bitch slapped the Kung Fu dude, who went running out of the room like a school girl. lol!
Bruce Lee was there, walked up to him after it was over, said that was the funniest thing he ever saw, then introduced himself. He was in a few of Bruce Lee's films.