Comment 1 for bug 266307

Unfortunately, this is the way VERP bounce processing is
handled. When a message is sent/returned to
listname-bounces+user=example.com@... it is scored as a
bounce for <email address hidden> (the VERPed address), and the
content of the message is never examined.

The theory is that the VERP address identifies the bouncing
address regardles of the recognizability of the notice
itself, so there is no attempt to recognize the type of notice.

It would be possible to run the returned message through the
recognizers and accept a recognizers determination that the
notice was non-fatal while still keeping the VERP address as
the address to use for the bounce report in the event that
the notice was not determined to be non-fatal, but that
wouldn't solve the problem for an unrecognized non-fatal
notice, and the whole idea behind VERP bounce processing is
that it allows skiping the recognition process.

It does seem wrong that a bounce is scored for a notice that
could be recognized as non-fatal, but there will always be a
grey area with notices that wouldn't be recognized as fatal
or non-fatal. If one decides to give the benefit of the
doubt in this grey area and not score a bounce, then we
revert to the non-VERP case in which only recognized bounces
are scored.

It seems that the real problem is that VERP bounce
processing isn't that good of an idea.