I can see it being a strict liability that if you make contact with the head and they are injured you will be in trouble
Which of course will mean more players go in head first and not protect themselves which will lead to more issues with head clashes
They'd need to make it a reportable / suspendable offence for that, too. If a player puts himself in danger then he cops the same suspension as the player who made contact with him. Of course if he's injured for longer than that then it's more of a symbolic penalty, but it may give players pause before actually putting themselves in that position.
That's the whole issue with this incident - it wasn't a player choosing to bump and being responsible for the consequences, which is what they've cracked down on in recent times. In this case, the distinction needs to be drawn between a bump and a collision. There was no bump here - it was a collision between two players both going for the ball. Just because Clark got injured and Mackay didn't doesn't mean that Clark is somehow less responsible for the collision or the outcome. He was just the unluckier of the two players.