LISTSERV's goal  is to  catch delivery errors  to prevent  mailing loops.
Even with a "Safe= Yes" list with a return address of owner-listname, you
are bound  to hit  a broken  gateway which sends  delivery errors  to the
'Reply-To:'  field and  to  need this  safety net.  People  who tell  you
otherwise have  no real world  experience with  e-mail. Now, there  is no
"standard"  of  any kind  for  delivery  errors.  There is  certainly  no
standard that says a mailer quoting  a rejected message should prefix the
header fields with >+blank. The problem your users are having is that the
mail program they use includes the  original mail headers when they reply
(maybe  this is  just a  default option).  This is  a religious  issue of
course, but LISTSERV is designed for normal, non-techie users who are not
particularly interested in  knowing, for instance and to  quote a shorter
than average example,  that the headers of the message  I am now replying
to were:
 
>Return-Path: <@SEARN.SUNET.SE:[log in to unmask]>
>Received: from SEARN.SUNET.SE (NJE origin LISTSERV@SEARN) by SEARN.SUNET.SE
>          (LMail V1.1d/1.7f) with BSMTP id 5404; Tue, 27 Apr 1993 17:18:39
+0200
>Received: from SEARN.BITNET by SEARN.SUNET.SE (LISTSERV release 1.7f) with NJE
>          id 6947 for [log in to unmask]; Tue, 27 Apr 1993 17:18:21 +0200
>Received: from UA1VM.UA.EDU (NJE origin MAILER@UA1VM) by SEARN.SUNET.SE (LMail
>          V1.1d/1.7f) with BSMTP id 5388; Tue, 27 Apr 1993 17:18:14 +0200
>Received: from ua1vm.ua.edu (NJE origin JFORD@UA1VM) by UA1VM.UA.EDU (LMail
>          V1.1d/1.7f) with BSMTP id 8118; Tue, 27 Apr 1993 10:21:04 -0500
>Return-Path: <@SEARN.SUNET.SE,@UA1VM.UA.EDU:[log in to unmask]>
>Message-ID: <[log in to unmask]>
>Date: Tue, 27 Apr 93 10:09:47 CDT
>From: James Ford <[log in to unmask]>
>Subject: Loopcheck question
>To: eric@searn, lstown-l@searn
>Sender: [log in to unmask]
 
and at any rate  they certainly don't want to see  that trash *before* my
actual comments.  It is quite possible  that there are users  who find it
vitally necessary  to include this  information at the beginning  of each
and every  reply they make  and are  frustrated by LISTSERV's  refusal to
accept  such messages,  but unfortunately  it is  not possible  to please
everyone.
 
  Eric