Very cool, thanks for starting the discussion on this JC.
I'm torn. On the one hand, we /are/ supposed to be in feature freeze and jeez, can I ever get this thing out the door? Well, I'm going to try hard to do so as soon as possible.
OTOH, this seems like such a useful and simple feature to add, it'd be almost a crime not to. What I would do is this:
If a post comes from a non-member, send a confirmation message to them. This would actually use most of the machinery already in place for confirmations.
If they confirm/reply, we'd add the address to the accept_these_nonmembers list and send all their held messages on through.
Here's a question though: what do we do if the default moderation bit for members is turned on? I don't want to get into a situation where a member's posting would get held, but a non-member posting would go through without some interaction from the list owner.
I guess if the default moderation bit is set, then we wouldn't send out the confirmation message, and non-member postings would have to be approved just like they are today.
-Barry