The old version said may and they changed to must. I believe the old version said the non-offending team may reduce the number in the scrum to match, but didn't have to, therefore they had the option of 8v7 or 7v7 scrum in the event that the other team lost a forward. This was changed to state they MUST have equal numbers and therefore any reduction in numbers on one team MUST be matched by the other team.
This u19 variation and update to state each team MUST have equal numbers in the scrum is a safety-oriented law, not technical or administrative. Reducing the scrum to 7v7 when a back is sent off has no bearing on safety and is not the intended outcome, despite the poorly written instructions.
At least we all agree that the Powers That Be did a poor job trying to clear this up!
The 2009 book (the year of the ruling) said:
A team
must have fewer than eight players in its scrum when either the team
cannot field a complete team, or a player is sent off for Foul Play, or a player leaves the field
because of injury.
2010 the book said:
Exception: A team must have fewer than eight players in its scrum when the team cannot
field eight suitably trained players in its scrum due to either the team not fielding a
complete team, or a forward player being sent off or temporarily suspended for foul play, or
a forward player leaving the field because of injury.
This stayed until 2018 when "may" was introduced:
When a team is reduced to fewer than 15 for any reason, then the number of players in
each team in the scrum may be similarly reduced. Where a permitted reduction is made
by one team, there is no requirement for the other team to make a similar reduction.
However, a team must not have fewer than five players in the scrum.
UNDER-19 Law variations
in 2022 the law book replaces may with must, suggesting things are reverting back to the pre 2009 ruling position. reason could there be?