This is a very interesting one! Yes, it was technically legal but it gets a bit more complex than that.
The question is - what was Pickett's intent in laying the tackle? Answer, presumably either to prevent Cornes disposing of the ball, or affect the disposal so it went off course. If he causes Cornes some pain in so doing well, that is part of the game. But, having laid the tackle AS Cornes released the ball legally, what was then his intention? Well, from the vision there seems to be no attempt to release the tackle! Instead he seems to deliberately hold on to the tackle well after the ball is gone and drives his opponent into the turf. I realise that Pickett and "hard football" defenders will say that it is all part of the one movement but it is not. Now, this is where Pickett's problem might arise - if the powers that be believe he clearly had a choice, but chose an action that could cause a defenceless player injury then he might be in trouble!
Just think through those words again "chose an action that could cause a defenceless player injury" and then run your brain's videotape of other Pickett incidents over many years and you may see a pattern may start to emerge.
By way of example I recall a collision with Simon Wiggins of Carlton where the same occurred - he chose an action to hurt, when he could have chosen an action which would not.
It might be an interesting week!
What a complet load of garbage ...both players body weight carried them forward ..Pickett would have had no idea if the ball was released or not ...I hope your posts improve from this load of crap