Look, I respect the heck out of Jim Brown as a football player. He was the greatest running back of his generation, and, if he played today, he'd still be great.
So when he says he never had to lower his head to gain an extra yard, and thus thinks it's no big deal that the NFL wants to penalize running backs who lower their heads and hit a defender in the head with the crown of their helmets, I'll buy that.
But I also see Emmitt Smith's point, which is that if you penalize a running back for lowering his head, you're actually taking away one of the ways running backs use to protect themselves. So you're robbing Peter to pay Paul, as far as the safety issue goes.
All I know is, I've seen a lot of footage of Jim Brown, and he never had to lower his head to protect himself (or bulldoze for the extra yard). And I've also seen this.
Does Sweetness pull off this, or half the runs he made as a player, without lowering his head? You tell me.