f it's a moderated newsgroup, as many are, the moderator can
simply refuse to put your posts onto the group.


true. However, on webtv, it works by banning the boxes by using the code on
your box.

Once the owner of a cerain club group sends the code, your webtv box is no
longer able to post to that particular newsgroup.

It gets banned by box, so even if there's other users on your box who did not
do anything wrong or did not make off-topic posts, they can't post in that
particular newsgroup, either.