qmail drop mail while spamassassin was down

[kerm1t]

SpamAssassin went down on my server for a couple of hours (until I restarted it). During this time, incoming mail just seemed to vanish - the qmail log showed it attempting to scan via SA and failing, but no sign of what happened to the mail. I would have expected it to simply be delivered to the user mailboxes unscanned (or even bounced), but this wasn't the case.

Any ideas? Has it really been deleted, is there anyway to make qmail deliver even if SA is down?