The real problem was changing my userid to that on another system.
The local administration decreed that all electronic mail not directly
related to Social Studies Computing is an abuse of the system.  Thus
I needed to change my entry on the list from this account to that of
another system.  I'm sure the UNSUB command would have done half of
that, but I would not have been able to instantly add the other account
to the (closed) list, and thus I would not have seen any of the mail
during the interim.  Let me expand on your question of security to
be able to make a correction of this type... changing the name would
not seem to cause too much problems, but would being able to correct
ANY field (such as userid/node) via some sort of CORRECT or UPDATE
command -- is this giving too much power?  If the argument is made
that this would allow the user to add someone to the list, the
counterpoint is that that user could have just as easily forwarded the
mail his/herself.