Currently, MB allows catalog numbers to have trailing (and leading?) spaces. It shouldn't.
Does it? It used to be possible but that was fixed and I can't reproduce it any more.
It does. See this edit, which corrects one of them (found by accident)
But that's cleaning it up, not adding it. The edit to add it looks to be http://beta.musicbrainz.org/edit/16558587 from months ago, definitely from before the bug was fixed.
Checking the DB, I don't see any leading or trailing spaces in catnos added since April.
Agreed — but the system still allows them to remain, which is what I hoped to be resolved for this ticket.
I've cleaned up the ones which remained manually and the server doesn't let you enter new ones, so there's nothing to do here now.
Actually, there is a bit more to do - enforce this at the database level. Now that you've cleaned it all up, that check can be trivially added.