If we are to go by the letter of the law, that's the idea. Referee's use their discretion on the field with high tackles, that's their prerogative. BUT, when the play is sent up to the video, I believe it should be a black and white.So you want a penalty to be awarded every time there is contact with the head of the player in the tackle?
The same happens when a player in an offside position is within the 10 metre radius of a player catching the football. The referee can rule whether they are involved in the play or not while the NRL has instructed the video ref's to give a no try automatically.