"LISTSERV site administrators' forum" <[log in to unmask]> 
wrote on 11/24/2006 10:39:52 AM:

> Not necessarily.  If you were using the CONTENT_FILTER, you could set 
the
> action for messages flagged as spam to MODERATE rather than DISCARD.  If
> you didn't trust your AV system enough to let it delete your mail for 
you
> (and I certainly don't trust mine that much yet), it could make a lot of
> sense to flag the message but send it on to LISTSERV anyway.

Which is a major flaw in most spam filters.  If it scores high as spam, 
they dump it into a holding location, that envenually ages out.  There are 
a few that score the message before issuing the final 250 Message 
Accepted.  If it scores high enough, it returns a 451 or for really high 
scores or virii, it returns 550.