A. yes but then they will demonstrate it in resisted drills and then live sparring. Did that happen?
B. lets pretend nobody cares and instead of judging the technique on their resume lets just judge the technique.
Then see my other response. He isn't teaching a technique, he is teaching two basic principles. The video is even called "principles."
A. Don't stay in the middle.
B. Don't use force against force and if your opponent does exploit the most obvious of side effects, loss of balance and the fact that, if you are out of the middle, the opponent is actually fighting against his own body, which contributes to the former.
@KPM I think we rarely see it in WC vs WC sparing simply because both sides are fighting using the same principle (never meet force with force.) This leads to each fighter, if equally matched, to essentially cancel each other out. However you do see it. Go back to that video I showed a while back of Sifu Jerry and put it on slowmo. I found this one. Start at :20.
For the first KO you don't simply see him trap, you see that he moves out of the center initially and, with the forward pressure of his initial trap, takes the balance from his opponent opponent because his opponent screws up. Instead of using footwork, which Sifu Keith illustrated in the video above, his opponent tries to resist with strength and the oppomentends up being forced off balance backwards. The opponent then tries to recover but again, since he is trying to use strength, Sifu Jerry, as he uses footwork, pulls him off balance forward. This causes the opponent to essentially fall into Sifu Jerry's punch.
Is it as pretty as Sifu Keith makes it out? Nope, fights are never that pretty in my experience, BUT the principles Sifu Keith was talking about are clearly evident in that encounter.
(PS I don't speak to any of the other fights in the video. That was simply the only one I could find with Sifu Jerry at MUSU that went "slow mo" so you could see the principles of footwork and taking advantage of the opponent going "force on force.")