See MBS-2529 as well

Might I suggest this as a rather simple improvement for one of the next iterations?
With MBS-2951 still under discussion I feel that we should have as few empty RGs as possible in the database (and there are almost 2K now).

This is not a dependency of 2529 or it would have had to be fixed before 2529.

Sure, but at the time that link was made there was no decision on how MBS-2529 was to be resolved (and indeed no comment by developers). Having modbot clean up afterwards in the separate process discussed here would probably have been a perfectly adequate solution since such a process probably should exist regardless.

Generalizing the ticket the ticket a bit, because presumably we don't want any core entities lying around entirely unlinked. Village estimate because we already have logic to do this for a couple of entities, so going that extra step shouldn't be a huge amount of work.

Setting due date based on when this task was moved to 12mo bucket.

In review at http://codereview.musicbrainz.org/r/1952/

On a related note, can we give some love to MBS-4892 in time for the next release?
It might affect this improvement, too.

That will not make todays release I'm afraid.