Good one, but I am curious as to how many 2x holdbacks there really are. Most HS athletic associations (including MIAA I believe) do not let you play sports if you turn 19 before the start of the school year.
This implies 2x holdbacks are not eligible to play sports their senior year.
I know that a few (many) years back a NYC HS football team forfeited every game and was vacated of a title because they rostered a too old player (the coaches didn't know was the lame excuse)
In the spirit of amateurism I think the NCAA should have a similar rule.
BYU requires their men to go on 2 year missions Casey Carroll (Duke defender) took time off to join the army