> >(5) Messages  sent to all-request should  contain the list name  so that
> >bounces can be identified with the list whose owner they are for.
>
> Since people often  own multiple lists, duplicates  are eliminated before
> the message is sent. So, there isn't  a one to one mapping between owners
> and lists. Another problem is  that all-request typically reaches a whole
> bunch of people. If each message needs  to contain the list name, you may
> end  up  with a  lot  of  small individual  messages  with  a handful  of
> recipients each, which take a lot longer to deliver.
 
Each copy of the message could be tagged with the names of all the
lists that a person owns.  I understand that a lot more copies of
the message would be generated, but I don't see that as a major
problem, since all-request isn't used very often.
 
Another way to handle the problem would be to have a command that
tells what lists have a particular email address in their header.
This would not be quite as effective because the mail might have
been forwarded before bouncing.