Head Clashes should not be a card
The rule currently is if there is a head clash the defender is given a card. It's one of the dumbest rules in Rugby Union at the moment. I was watching a game on tv recently where the ball carrier basically led with his head and head butted the defender. TMO gets involved and would you know it, the defender is sent to the bin.
In the NRL a head clash is ruled as accidental as the idea that someone is purposely trying to get concussed by head butting someone is ludicrous. In Union though stupidity reins and now ANY head contact no matter how stupid results in 10 in the bin. Whacking someone in the head would also hurt so I can't imagine any player is trying to do it.
Maybe that's a good tactic, get the ball and run up to the oppositions best player and head butt him. Bam, he's in the bin.