http://codereview.musicbrainz.org/r/1276/

I entered a "Move CDToc" edit while cdtoc already exists on target medium.
Then I've received a mail from Modbot telling me "This CDTOC cannot be moved to So80s 5, as it already has this CDTOC. It must instead be removed."
Judging by the tone of the last sentence, I was sure the edit had failed.

But the edit was in fact open...