>     How did the system know to do this?

Because the auto-reply went back to the right place, which is surprising
for cc:Mail, quite frankly.  See below.

>     What is the reserved 'owner-busint-l' mailbox and does it serve other
>     purposes?

It is the address to which all properly-configured mailers are supposed to
be sending bounces to.  If you are familiar with the Internet RFCs for mail
this is the address that goes into the RFC821 MAIL FROM: field.  This is
done <specifically> to keep bouncing mail from going back to the list, but
of course whether this works or not is completely dependent on whether or
not the remote mail server is compliant with the standard.  cc:Mail usually
isn't, thus my surprise noted above :)

>     As list owner, can I shut off these messages to me because I don't
>     want to see all the auto-reply messages either?

If you turn on the Auto-Delete function and set it to Full-Auto, you might
not see these anymore, assuming that they do actually get sent to the
owner- mailbox.  Otherwise, no, they're assumed to be delivery errors and
are treated as such.  You could probably filter them out if you have a
filter mechanism on your mail client based on some rule (like dump anything
that has a header that includes the words "Auto-Reply:" or something like
that).

Nathan