It can be configured not to return bounces.  For non-listserv 
installations, returning bounces does perform the useful task of 
informing legitimate people that their email did not get through and 
they can then take appropriate action.  It's possible to mount a 
reverse attack, i.e. have some poor unsuspecting individual get 
thousands of real bounces because their email address was used in one 
or more large spam mailings.

I've found it's worth keeping on.  We use SPF to help prevent our 
user's email addresses from getting hijacked.

John

At 12:43 PM 11/1/2006, you wrote:
> >I use a Barracuda spam firewall with excellent results.
>
>I see around 20 back-scatter inappropriate 'returns' per day
>of spam that said it was "from" false joe-jobbed addresses,
>each sent from different Barracuda Spam Firewall installations.
>
>Because these "bounces" are each unique, I wonder if,
>perhaps, that dang Barracuda Spam Firewall might
>DEFAULT to "return" spam to the innocent e-mail
>addresses that the disgusting, lying spammers put
>on the From: line?
>
>While I suppose this behavior is RFC-legal, I would
>prefer another option. <grumble>
>
>http://www.immune.com/SpamNotFromImmune.Com.html