Yes, such a client side filter will prevent end users (us) from seeing such emails. But being the email administrator (postmaster) that I am I feel that such a solution is a patch and a poor one at that. Why don't we resolve the real problem, that being to remove the problem email address from the mail list. Grant. . . .
I suppose that everyone posting to the list gets this mail - at least I get it ervery time. Like Jason already posted, adding :0 * From.*postmaster@xxxxxxxxxxxx /dev/null to my .procmailrc solved this and mekes me feel better :) Have a nice time, Joerg