I was hoping someone would start a thread regarding this type of tackle. Is it illegal? Honestly I don't know, good arguments have been made here about its legality. Is it dangerous? Most definitely... I don't have much of a problem with the danger posed to the tackler as it is their decision to make that type of tackle and they can deal with the consequences on their end but I have serious issue with the danger to the attacking player.
Chopping at a joint such as the knee from front/side on is incredibly dangerous... as D-Box pointed out -
If you look at the individual getting tackled there are two potential knee injuries
- If you have enough forward momentum and get hit on the shin you can rupture your PCL by pushing your tibia back against your femur
Even if the tacklee is standing still and the tackler hits their knee with the shoulder from the side you can rupture both you MCL and your ACL. (This is the risk from the NFL chop block)
Add in the size of some of the blokes making these tackles at Super level as well as the force at which they throw that weight into the attacker and you could have a recipe for very serious injuries.
One or two refs in QLD Rugby have started penalising this type of tackle referring to it as dangerous and sometimes no-arms when pushed on the point. Also just about every player (amateur & professional) who I've discussed it with believe it to be dangerous and verging on a cheap shot as there is nothing you can do, as an attacker, about it. Check out the reaction of the Hurricanes no 8 after Saia's tackle. Earlier in the preseason I witnessed one player do this to another in a 15 on 15 contact "game" at club training... the tackler coped a fair flogging for his efforts as he hyper-extended the other players knee.