From http://bugs.musicbrainz.org/ticket/3680

To allow editors an opportunity to respond/discuss a negative vote, the edit's expiration date should be extended. This would help avoid edits being voted down right before their expiration date.

See mailing list discussion: http://www.nabble.com/Last-minutes-votes-to16771614s2885.html

EDIT: I'm changing this ticket to more generally be that, if an edit gets a no vote (or several), other editors, including the original editor, should have time to respond. This includes cases where the votes are unanimous, which means that it can't plainly be just extending the expiration time – even edits with sufficient unanimous no votes should stay open for a period so they can be responded to, both by the original editor and other editors who may not agree with the 'no' votes.