I appreciate your post, Lenny.
Let me make two points and two points only:
(1) Every single post is available to ANY student via the LIST
archives. Which means regardless if any student is "on" the LISTSERV
he/she has access to the discussion.
(2) Any student may write and send an email to any address that is valid
and capable of receiving emails. The address of [log in to unmask] is
capable of receiving emails.
If listserv privacy is your issue changes need to be made.