One thing that I would say is a clarification is the example of the offensive lineman rising from a crouched stance at the snap, taking a half-step back, then diving at the opponent. Shaw says this is to be considered "initial charge," so he would still be allowed to block below the waist from the side (although, in the example, his block is from the front, which would be legal, even after his initial charge). I was wondering if such 'rising' action before diving was to be considered a 'second action,' thus, eliminating the side block. But this clearly tells us otherwise.
But, this is distinct from a lineman that rises, takes a pass blocking stance, and begins his effort to 'push block' the opponent. At that point, his initial charge is expended, and he would no longer be allowed to block below the waist from the side.
I believe the first practices began in Texas yesterday. I heard that a Head Coach was talking with an official and asked if there were any new rules.
Well, I guess that's better than during the referee/coach conference for their first game. But, I'd bet something like that happens, too. More likely: Referee: "Coach, you are aware of the new blocking below the waist rules - right?" Coach: "What new rules?"