How are they going to determin if it is intentional in the future? Another subjective-bullshit rule. The ball went backwards with no seperation, it wasnt a loose carry.It doesn't matter if it goes back.
It touches a player in front of him which constitutes a knock on. Right call was made, just like the right call was made for the Peter Wallace no try last year when Josh McGuire knocked it out trying to make a tackle.
You couldn't say he was definitely playing at the ball so they couldn't give it.
If he intentionally played at it, it would have been try so it doesn't really open the door for players to deliberately knock it out to get a knock on call.