[tor-relays] Why should we avoid adding bridges fingerprints in MyFamily?

Hi all, Quick question about the fingerprints of our bridges. It's clearly written in torrc that we should not include them in MyFamily. I don't well understand why, especially because: - Every bridge, and their fingerprints, are publicly listed on Tor Metrics; - The contact email is disclosed for each of them, and it allows our bridges and relays to be easily linked to a same operator. (or should we use a different email address for each bridge?) Best regards