http://tinderbox.mozilla.org/showlog.cgi?log=Mozilla-l10n/1231158661.1231158688.8897.gz&fulltext=1 looks like the builds don't fail if the upload fails. Probably lacks a haltOnFailure.
This is my fault, I'll take care of it.
Created attachment 355590 [details] [diff] [review] flunk on failure for uploads
Comment on attachment 355590 [details] [diff] [review] flunk on failure for uploads Checking in factory.py; /cvsroot/mozilla/tools/buildbotcustom/process/factory.py,v <-- factory.py new revision: 1.71; previous revision: 1.70 done
...And the master has been reconfig'ed for it.