I've had this problem, too, on a list of similar size.  I
looked for a magic bullet and couldn't find one.  But
eventually the problem went away.  I suspect it's like cooch
grass in the garden: you just keep pulling at it and
eventually you get ahead of it.

> As we're getting into the summer, lots of people on the list
> are going away on summer trips (this is a list for high school
> students), and they want to get off the list. However, even
> though it says on the bottom of every message (in the footer)
> how to unsubscribe, many of them don't know how to and just
> e-mail the list saying "Please take me off the list" even
> though I've explained at least a couple times in the past that
> they shouldn't e-mail the list because it fills up peoples'
> mailboxes.

I think it would be possible to set up a filter to pull
specific messages out before distribution (pulling out every
message whose first word was "please" would probably be about
70% effective), but I don't know that it would be worth the
hassle.  What I did was set up a filter on my own mailer so I
could deal with them in batches, and write a boilerplate
message explaining why you shouldn't write the list.

Lowered my workload -- and I think eventually worked (I just
checked the archives and there's not been an unsubscribe
request to the list in a year).

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