Performing royalties are collected centrally by the PRS and distributed to artists direct in respect of airplay and performance returns.

Receipt of cheques in respect of this are usually the first an artist knows of the release of a CD-R of their previously hidden work. I have mentioned this, many times, in previous threads.

CM could not withhold these royalties even if they wanted to.

Mechanicals are an entirely different matter.

A producer proposing to issue (or re-issue) a recording is supposed to obtain a licence from the MCPS and an above-board pressing plant will insist on this before doing the run. Thus the artist will receive royalties according to retail sales.

If the release is on CD-R there is clearly no check on sales, though a producer ought in theory, make annual returns to the MCPS. Who checks?