In my opinion, and it goes for either side.....if a player is running full speed into a heavily populated area with equipment and benches, and someone on the sideline watching the play doesn't try to safely grab the player once out of bounds to help slow the player and reduce the chance of serious injury, then there should be a flag for unsportsmanlike conduct. By definition, that is a pure example of unsportsmanlike conduct.
I'm all for bone crunching crack-back blocks on the field. I even like hitting defenseless receivers across the middle of the field because it's a play on the field. But all players should care about other player's safety after the play is over. Specifically when running full speed into a blind area.