Surrender Tackle
Occurs when the player in possession surrenders his run in or at the line.
He certainly surrendered his run and indicated he wasn't going to run on that play and was going to accept being tackled. The rest of the quote says things the defender may or may not do at their discretion.
He feigned he wasn't going to compete on the play then opportunistically changed his play. It wasn't necessarily a dog act. But it wasn't fair dinkum play.
No, he never started a run, he collected the ball from dh and took a knee. Walters only initiates contact AFTER Trell dives at the line.

Next you'll be saying dummying the pass isnt fair dinkum.