No, the list is not fine. It should set the Precendence level. Your method would automatically assume that anyone who BCC'ed you was a mailing list.
That's OK - I don't want to send vacation mail to folks that BBC me either. Useful rules (taken from 'man vacation'): No message will be sent unless login (or an alias supplied using the -a option) is part of either the ``To:'' or ``Cc:'' headers of the mail. No messages from ``???-REQUEST'', ``Postmaster'', ``UUCP'', ``MAILER'', or ``MAILER-DAEMON'' will be replied to (where these strings are case insensitive) nor is a notification sent if a ``Precedence: bulk'' or ``Precedence: junk'' line is included in the mail headers. Anyhow, enough non-operation junk for now. --asp@partan.com (Andrew Partan)