The specific scenarios that you speak of are irrelevant. What are helmet-to-helmet hits by the Steelers, Patriots, & Falcons today are going to be ones by the Packers, Chiefs, and Cowboys tomorrow. You get my drift.
The only thing worth mentioning is the impact of this change. Try this one on for size:
Just like in World Cup soccer, you're going to see WR's "diving" like crazy. Crappy QB's will continue to lead their WR's across the middle, and when they're popped, IF THERE IS A SLIGHTEST CHANCE THAT A CHINSTRAP GRAZED THE WR'S HELMET, he will be taught to STAY DOWN. Defensive players WILL get suspended because of WR's "diving." Before there was no reason to fake a injury except to stop the clock. Boy, that has changed now. And it will. Guaranteed.
Now you have the opportunity to get a division rival suspended, maybe even for the playoffs. What better way to play spoiler than that?
So everyone enjoy that when it arrives, which may be as early as this Sunday.