They trialled having an offside line at the tackle a few years back with disastrous results.
That was the ELV they tried in 2008 with the
"offside at the tackle" law. IMO, they went about this the wrong way. They needed to have some kind of provision that offside players who are in the act of retiring as they "chase back" to a tackle will be made onside when the ball is cleared, but that players who loiter in an offside position at a tackle must retire all the way to the offside line. Without such a provision, a midfield break can become completely impossible to legally defend.. as the video shows.
https://www.youtube.com/watch?v=10yjOe3zSQw
Having a provision that moving players are legal but stationary players are infringing its not without precedent in the game - see Law 19.12 (b)
Personally, I wouldn't like to see the "Breakdown" trial from last season's Mitre 10 Cup adopted as a result of this morning's game. That would simply be a kneejerk reaction.
Nor would I, although the main problem with that trial is that they also made a Law change which made the jackler release the ball if someone bound to him. This resulted in three examples of "Merton's Law (a.k.a. the Law of unintended consequences)
1. Defending teams committed few, sometime no players to the ruck.
2. Those players who did commit tended to stand more upright and tried to kick the ball through.
3. Breakdown turnovers were almost impossible to get, so teams stopped trying.
The end result was endless phases in a
"procession of possession" as defending teams lined the trenches while attacking teams tried to batter their way through.
The experiment was an abject failure IMO.
I would love to see Italy use the tactic against the All Blacks to see how long it would last. The NZ guys and the Irish seem to be a step ahead when it comes to their players knowing the LoTG.
I reckon the tactic would last two to three rucks at most
To really use this tactic well, you need to have a couple of players back and in line from the tackle to prevent the pick and drive, but unless they get very close, the pick & drivers are going to make the gain line, and if the defenders get too close, they will end up being drawn into a ruck.... game over.