With respect to BCC’ing – I agree. I use BCC on almost every email I send, but I am BCC’ing to me. That gives me the ‘GMail Conversation Thread’ effect in Thunderbird without violating your BCC rule.

Actually, now that I think of it, my wife and I regularly BCC each other on things of mutual importance like emails to our suppliers regarding the running of our B&B and the like.

But those are rather innocuous BCCs which – I think – only violate the letter of your rule and not its intent.