We don't want to standardize notions of etiquette (though some mailing
list admins might try to standardize it within their own lists).
What we want to do is to keep everyone happy by letting the one who
thinks
some behaviour is rude say so in a way that others can respond in the
(to
him) polite manner.
What I want is to get rid of the conflict between two valid concerns.
One is that senders should be able to specify (both to their MUAs and
to recipients) who was intended to receive a message without having to
worry about which recipient addresses include other recipient
addresses. The other is that recipients shouldn't have to see
duplicate messages.
The "rudeness" arguments are a bit specious. I assume Charles does not
intend to annoy me by refusing to copy me on replies to my messages. I
assume people do not (usually) intend to annoy recipients who get
duplicate copies by explicitly including them as recipients of replies.
What we have now is a system that makes it easy to be annoying, and
also makes it difficult to reliably avoid being annoying. I think we
would do well to reduce the annoyance. I just don't want us to have to
sacrifice message context or flexibility when we do so.
Keith
p.s. fwiw, the Mac mail client doesn't seem to handle group syntax
correctly - it doesn't let you delete an address within a group, move
it to a different header field, etc. nor does it let you perform
operations on the entire group. just a data point.