Both are obscene hits to the head. Would be happy to see the players who do it serve lengthy bans.
The problem is shades of grey and they are open to different views.
Take the uncertainty of challenges away from the eye of the beholder and it will be a good decision.
I still think Sam Burgess challenge on Fui Fui Moi Moi was wrong but it is held up as an example of hard play and pay back.