[Mailman-Users] How do I prevent subscribers from sending to -bounces address instead of list address?

[Stephen J. Turnbull]

Mark Sapiro writes:
 > On 03/04/2016 10:33 AM, Hirayama, Pat wrote:

 > > [Users] send new messages to the list [addressed to
 > > listname-bounces]. Aside from repeatedly telling the users that
 > > they need to send to listname at domain, have any of you found a
 > > better solution?
 > 
 > You can't control what MUA's your user's use. Attempting to educate
 > them, at least in most user populations, is futile.

I agree that this is a hard problem, and not one we should try to
solve in Mailman 2.  But I wonder if we can't do a better job on
behalf of list admins in Mailman 3?  What I have specifically in mind
is to reject the message in Mailman if From (or Sender?) is a list
member, *after* checking for "actionable" messages (eg, DSNs for
bounce processing).  Are there any legitimate reasons for a subscriber
to send mail to listname-bounces?  The is_subscriber test would avoid
99% of backscatter, as well, I hope.

If people consistently get an automated rejection, most will learn (by
now they've figured out that human owners are a lot more flexible and
helpful than even the best software == GNU Mailman).  Some will scream
at the list owner, so probably this feature would need to be an
option. :-(