The obvious reason is because they won’t be able to be insured unless these steps are taken. I would imagine that the conditions will be imposed by insurers before they consider insuring the sport. It kind of gives them some rope to put up the premiums also even with the tackle height reduced.
From what I see a number of the head injuries happen more at thigh/hip level anyway. Take Batchelor at magic weekend last year. You rarely see head injury from high tackles these days anyway.
The issue is the game will evolve into something different. There are a number of issues.some immediate ones from a fan perspective:
1. Clubs, coaches and players will exploit the change - catching a player high whilst they drop or lower into the tackle has already been a recent talking point. You can’t tell me this won’t be coached. Drop a couple of inches going into contact so you get hit on the upper chest. It’s a gift of a repeat set and there will be clubs who use this to the fullest. You couldn’t prove it either if it’s small margins.
2. Who draws the line? It’s more pressure and more grey area on the officials to police. Where one offivial sees a tackle above the line another may not (especially at high speed contact). This is going to be a lottery and a minefield. Officials will face the brunt of it too and they’re already receiving a high level of criticism for what I feel is more a lack of resource and support from the governing body. There is an answer for this….. every team shirt has a line on the shirt going from pit to pit which can be a tool to judge by. It won’t be perfect but gives some benchmark at least. Either way officials are going to really get the brunt of this change. I actually feel really sorry for the referees.
3. Grappling in upper body and wrapping the ball will be very difficult to do without being penalised for. Players who carry the ball high up especially. We will end up seeing a ton of offloads potentially and it being more like a hot potato.
4. The 6 again currently speeds up play and is a tool teams use to put others on the back foot and exploit to get further repeat sets. Is the game currently too fast for this kind of change? I think since 6 again the game has become a lot more scrappy and more direct and less expansive. Teams can hammer fast runs behind the play for repeated sets at pace to inch down field and keep teams on the back foot. This change would make it all the easier to do this.
I feel that the sport is backed into a corner with this with very little option but this will signal a huge change.