I am not at all sure what you mean by automatic program, but it's
certainly possible to forward mail from your listserv to any other
address, including, of course, the addresses of people you unsubscribed.
Deleting subscribers only affects the automated procedures of LISTSERV,
they are taken off the distribution list, but this doesn't mean they
can't continue to receive mail fro anyone willing to pass their messages
on to them.  The fact that your list is private only means that you can
request that subscribers don't forward messages to others outside the
group; it doesn't mean that you can really enforce.  As one of my
colleagues on this list reminded me a few months ago when I was
annoyed at a personal message being forwarded to exactly the wrong
party--(I paraphrase) NO e-mail essage is ever entirely safe. You are
at the mercy of you listmembers.
 
It does seem to me that under the circumstances you would be much
better off not to permit listmembers to review the list, especially
if you have to filter obnoxious former subscribers who might in turn
get upset when they see their address in the header of the list.
 
Again, an no fancy  program is needed!   Practically every mail utility
in the cyberworld permits the construction of lists to cc a mesage.
You can't trace someone else's mail unless you can talk someone into
forwarding you one of the forwarded messages, so you can look at the
header and figure out the route it took.
 
Peace, Ingrid
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