Well, try to write a program to recognize this (easy) and extract the
right address to delete. Then run your program on a couple hundred sample
delivery errors from various sources and see how many times it deletes
the wrong user, or nobody at all. Then see how often it deleted a user
for a temporary error. LISTSERV only processes formatted delivery error
reports like those generated by LMail, PMDF V4.2 and MX V3.2 and above.
With these reports both the address and the temporary/permanent nature of
the error can be determined safely.
Eric