Dave, the bit that treats leaving the pitch for a concussion assessment same as blood. Temporary replacement for 10 minutes (not enough IMO).
It's the Law 3 "Law Amendment Trial" in the 2015 Lawbook; it starts:
[LAWS]
LAW AMENDMENT TRIAL
Temporary replacement - head injury assessment
In all situations, if there are any indications of concussion a player MUST be removed from play. This is known as Recognise and Remove. For tournaments and matches approved by the Union or Rugby body having jurisdiction and with trained healthcare professionals, a temporary replacement may be used for a player who has a head injury where the diagnosis is unclear.
(a) When a player leaves the field to have a head injury assessment that player may be temporarily replaced. If the player who has been temporarily replaced does not return to the field of play within ten minutes (actual time) of leaving the playing area, the replacement becomes permanent and the replaced player must not return to the field of play.
...[/LAWS]
Which I read as saying:
In all games, anyone with indications of concussion leaves the field.
If there are trained healthcare professionals around, and the tournament/match is approved by the national Union (ie it's not eg a friendly match), then the player can come back onto the field if s/he passes a pitchside assement within 10 minutes of going off - and can be temporarily replaced while being assessed.
If there are none, or the game isn't approved by the Union, then he stays off and any sub is permanent.
So for a player with indications of concussion it's
either pitchside assessment
plus temporary replacement;
or "your match is over" and, if available, a permanent replacement; depending on the status of the match.
Which would seem to mean that USA Rugby doesn't get an opt-out of temporary substitution while an assessment takes place; although, in another thread, SimonSmith indicates that they have taken an opt-out.
