The essence is that reissues on CDR (if without MCPS registration) might infringe third party rights, in which case MCPS might take an interest.

Two MIGHTs but worth a try, to get the big guns into the battle.

Think how difficult it is for anyone to determine whether their 'folk' songs and their tunes are really in the public domain.
(Or whether the McPeakes have copyrighted them)