Other than simply doing a mass-delete of a userid@node when that address
is no longer valid, how do you "handled" the case when that userid@node
is a colleague and has died?  E.g., do you do so QUIETly and perhaps then
edit the report and e-mail the list-owners (-REQUEST) why you have done
the delete; or perhaps you do a non-QUIET delete and await inquiries
(sometimes angry, either because the list-owner did not interpret the
auto-generated message properly, or thought they were the only one that
could affect subscription), etc.

Our organization has thousands of lists, and some proportional larger
number of thousands of list-owners spread across the university and world.

Pete Weiss @ Penn State