On the basis refs clearly allow rolling post tackle to gain an extra metre (and this is "all" levels from what i see ) I cant see that the use of the arm in the manner described by Phil as any different.
Though this use is different to that demoinstrated in the OP viseo which is all about height in preperation for being driven from behind - at a height that a tackle is almost impossible
At least with the roll it’s generally easy to identify a BC rolling once with momentum or a half-roll both of which are to get the ball on the attacking side. There is some gains in ground but that’s almost secondary to getting the ball available to play for a quick recycle by your team. On the other side you have the BC who could easily present the ball but instead takes an extra roll to gain ground and slow down the jackal. The former we allow, the latter we do not.
Maybe that’s how we treat this? If you’re tackled and as brought to ground you put an arm down, gain a little ground but the ball is available then play on. If you’re a bc stumbling from a tackle or fluffed pick and go and you put the arm down to momentarily support then play on. Put your hand down and then get a fellow player to launch you low then penalize for off feet?
The next question - is it foul play? So if bc sets up, arm on floor, then picks up the ball and then their teammate launches them and we have head to head contact with a defender who is as low as they can go … what next? Penalty against the:
Defender for not getting low enough?
BC for dangerous play by leading with their head?
Launching teammate for driving teammate into head on head collision?
Red card?
Or accept two players on the deck bleeding and maybe out cold as just a “rugby incident”?
I’d need to see the play that
@Phil E observed but as described I’m generally going to be ok with that. BC with the ball trying to dive or drive a gap to ground a try, again generally going to be ok.
But the deliberate setup with BC then launched forward, I’m having a hard time accepting that the more I think about it - and maybe that’s what the whole SARU move was about? WR were unlikely to rule specifics this close but maybe they just wanted all the refs chatting about it before they face Ireland?
Of course, I still need to be able to spot it in the first place as I have no TMO or refs on touch for me.