On Thu, 21 Dec 2006 10:49:09 -0500, Steve Howie <[log in to unmask]> wrote:

>Subject line says it all. Is there any way to a) prevent a list 
>subscriber from unsubscribing from a list and b) prevent the subscriber 
>from setting their options to NOMAIL?

This question has been asked numerous times and lengthy discussion of it may
be found by searching the archives of this list and of the LSTSRV-L list.  The
short version of the discussion is that this question would only come from
somebody at an institution, such as a college or university where there is an
attempt to force people to read "important messages" from some administrative
source.  This is fundamentally a human issue that cannot readily be solved by
technology.  

As Pete points out, keeping the user from unsubscribing or setting NOMAIL will
not and cannot force them to read the "important messages".  They can delete
w/o reading, or otherwise avail themselves of the right not to know something
they have decided is not "important" to them.  That said, there is a
(difficult) way to do what you want, which requires Site Admin privs and
external programming and therefore needs to be asked on the LSTSRV-L list.
(actually just search the archives there, it has been answered at least 5
times in the last 6 years).  There are also other ways of sending such
messages, such as using a database table (from which self-unsubscribing is
impossible by design) as a source for the mailing instead of a standard
LISTSERV List.