This person legitimately subscribed to the group on May 30th so
unfortunately there was no good way to prevent this. I've deleted the
offending message, banned the sender from the group, and complained to
abuse@....

To repeat what I said in message #498, there is a "first post from a new
member is moderated, unmoderated thereafter" option but spam hasn't been
a real problem so I haven't wanted to resort to that (esp. if someone
new joins up and wants to try to post tickets to that night's game and
I'm not around to approve it, etc.)