Some mail systems generate errors  in a format LISTSERV understands, some
don't.  If  LISTSERV doesn't  understand,  it  does nothing,  because  it
doesn't know whether the error is permanent  and who is the victim. If it
understands  and auto-delete  is  enabled,  it removes  the  user upon  a
permanent error.  If a user  is regularly reported as  nonexistent during
the weekends,  when he in  fact does exist,  he should get  his technical
people to fix this problem. If the  post office returned all the mail you
received on Mondays  with a note saying  you do not in fact  live at that
address, I'm  sure you would take  prompt action, and wouldn't  blame the
newspapers you are subscribed to for  not resending every other day "just
in case". But, for some reason, most  people think it is ok for computers
to occasionally  claim that your address  doesn't exist. As long  as this
attitude prevails,  computers will  continue to do  that; why  spend time
fixing a problem if it is not perceived as a problem?
 
  Eric