2018 Rd 8: Post Game Passion: Carlton vs Essendon

[JonHenry]

It is covered in the rules the game.
(b)pushes an opposition Player in the back, unless such contact
is incidental to a Marking contest and the Player is legitimately
Marking, attempting to Mark or spoil the football;

Geez this stuff has come back into the game a lot.
In general play, and not in a marking contest it seem's like you can push anyone under the ball or past the ball these days