After an unmoderated post has got through to the group, which may receive complaints from members. This is a sample Admin message you could use to send to your group
ADMIN: INAPPROPRIATE MESSAGES
Every now and then an unmoderated member posts a message which is against the Membership Guidelines of $groupname. It's usually an honest mistake because the member just didn't realise it was against the rules.
When a member who is not moderated posts something, it immediately goes out to all the members who receive individual emails. All the mods can do at that point is to delete the message from the group site, and put the poster on moderation to prevent future errors by that member.
We don't want to moderate the whole list, because the problems are really pretty rare, and there's no sense in slowing down everyone's messages to prevent those few from slipping through.
So, if you receive a message that is outside of the groups mission (pet ads for breeders, for sale/trade, seeking jobs, personals, or anything illegal or adult), you might want to check the group site to see if the message has been deleted. If it has, then you will know that the moderators have it under control. If it's still there, please forward the message to the moderators at: $owneremail.
One more thing... please don't comment about these inappropriate messages to the whole list or else we will also have to put you on moderation, too.
$myname and the $groupname moderating team