It seems to me that you guys are over-analyzing the situation; The guy hopped bakwards.
Lifting your feet up as you fall backwards can happen to anyone and it is a pretty normal reaction. I have had people push me before and thats how I hop back, and I have no Southern Taiji trainning. You can always look at a video and say; "my, that hop looks fake," but how would you
hop back if you were pushed? To take the matter further, how do you even know how a person would hop back if hit with "chi energy"?
Its strange; do we really have to have Michael suspend himself from a rope (a noose?
) and push back another guy on a rope to demonstrate that he's telling the truth? Isn't that just a little picky? The point made that some people are trainned to jump back at anything is a good one but some of those guys looked to be pushing very hard. (They could have been faking that too