oh boy. In the example above, “Mary” and “Jane” are the same person (I started thinking Mary was the other BCC, then made it Jane). What a mess. Sorry about that.
Perfectly explained; I understood what you meant.
Yes, as you stated, revealing to all who are on To: and C.C: but not to the other BCC....even though the other BCC won’t see the reply to all, by replying to all, I can alert the others of the game being played. Eventually, the game is revealed to everyone in the circle if everyone is moving into CC and To positions in subsequent emails.