Valdis:
 
One way that it *could* be done would be to have LISTSERV recognize one
or more authorized individuals at each node with the power to send a
list of deleted userids to be purged from all lists.  For nodes hosting
LISTSERV, it could be the Postmaster, but that would probably not be
acceptable at all LISTSERV host nodes and wouldn't cover other nodes at
all.  LISTSERV would have to be prepared to broadcast the entire list to
every node in its file of peers.  That would create a lot of extra
traffic unless most userids were in fact subscribed to lists around the
network, but it would be necessary in the absence of a central directory
of users, either everybody or just list subscribers.  Even then, newly
added LISTSERV sites might not get the mass-deletion request unless
every site kept its peer list up to date.
 
I am sending this back to LSTSRV-L only, hoping all REDIST-L subscribers
are also LSTSRV-L subscribers.