> Anyone know why a message is held for authorization because
> of "Implicit destination"?  The address is a member of the list
> (postings restricted to members-only).

Does the To: or Cc: header mention your list name?  If you have
'require_explicit_destination' set to yes for your list then it
will only allow messages that mention the list in one of these
headers.  

It's very effective for the prevention of spam, but has the side
effect of blocking Bcc'ed messages, etc.

Chris