Hmm. It would be better, if it could be switched on and off. I understand what reuhop means. I.e. I have songs, where album is tagged xxx (Remix) or xxx (EP). All scrobbler I've tested (especially) in android won't scrobble it the right way. Albumtag will be completely ignored in most cases and MB won't sync back. But I also understand the other arguments.
Yes, if you have inaccurate album titles in the album field, last.fm will not be able to match it up with albums in its database. I do this too ([2009 Remaster],[DCC Gold], etc).
But, if I'm not mistaken, because last.fm sends back all the information you've sent it whether or not there's a match in last.fm's album database, MB is able to match these back up with what's in your library and synch the play counts and all just fine. That's the way it seems to be working here. If I play such a track in my car and then come home and open MB, the play shows up.
It's just that it won't match to an album last.fm knows about if you look at it on last.fm. So, basically, you won't see a cover for it there.