It's illegal shepherding.What about taggers who just face the player they are tagging at a stoppage and move all over the place stopping his path to the ball/contest, has no interest whatsoever in getting the ball himself. Lachie Neale cops it every week and yes I know we do it as well.
I just don't see it as fair play, if a defender did that in the F50 re an incoming marking contest it would be a free against every time.
There's a rule book. But the AFL has tinkered with interpretations to the rules so often that all we have now are interpretations but not many rules.