[Exim] message delay warning messages

Hello,

I have an _important_ user who wants me (or more precisely, the
Exim-based mail servers that I administer) to stop sending message-
delayed warning messsages and non-delivery reports to "non-
human" senders. Over the past weekend he exceeded his mail quota
and as a result, message-delayed-warning-messages were sent in
response to messages he received from a listserv-based mailing list.
He is quite unhappy that he may be suspended or removed from
that mailing-list because of the warning-messages generated by him
being over-quota. However, to make matters worse, the message he
received in response to the message-delay-warning message
suggested that the fault lie with my mail-service for sending such
warning mesages in the first place!!!!!!

I see from the exim-users archives that this matter was discussed
over four years ago but the discussion appears to have ended
without any conclusion, action, wishlist item or statement?

My question is: can [or should] I configure Exim _not_ to send
message-delay-warning messages and NDRs to certain addresses?

Thanks,
Nick.

--
Nicholas Blackaby, ISD, UMIST.
n.blackaby@???, 0161 200 3208