Mailfilter

Hi,

I know this is a bit off topic, but it's concerning something
that I believe most ppl find a bit annoying.
 Like most other mailinglists the postgresql ones suffer from
occational "unsubscribe" msges in the list itself. Wouldn't it
be possible to write some filter that stop these mail and return
unsubscription instructions to the sender?

Regards,
Patrik Kudo