The way I understand it, it’s the movement of the brain against the inside of the skull (due to a sudden stop/start) that causes brain injury. How does extra padding on the outside help to prevent any of that? Honest question. I’m not a neurologist, and I only played football through high school. Had plenty of headaches from impacts, but I don’t think that extra exterior padding would preclude the brain from freely moving within. In my opinion, the guardian caps are just to make the spectator feel better, and they actually do nothing.