Adam84
Rod McCall (65)
The defending team can only legally sack a maul before it forms, which in practical terms, means immediately the moment the jumper hits the ground.
Added to that, the ripper must also act at that moment as well, otherwise it's obstruction
Therefore timing is critical and sometimes attacking teams get a bit ahead of themselves
hence why if the defending teams opt not to engage, and the attacking team forms a maul, its considered an obstruction also. I haven't seen that tactic used for a while though, so maybe its not allowed anymore.