I'm having trouble understanding what Listserv does with these.

Some of them come to me as listowner, identified as errors, of a
couple of kinds -- sometimes "The enclosed message has been
identified as a delivery error for the xxx list because it was
sent to [log in to unmask]"; sometimes because "mail
origin is listed in  the "Filter=" list header keyword (or its
default value for the xxx list)."

Some go to the original poster, as Pete suggests:

> If a poster to a list receives an OOO from a subscriber, then
> indeed, you would not be able to control that via automated
> facilities.  From time-to-time, YOU should post some
> productive or administrative message to the list and
> "experience" these first hand.

And, at least once in the last month, one was distributed to the
entire list and stored in the archive.  I can't see what the
factors are that determine what happens when people set these
things up, and I'd like to be able to advise them how to do it
to cause the least inconvenience.  Where is this documented?
Has anybody else run into this?

-- Russ
St. Thomas University
http://www.StThomasU.ca/~hunt/