Merge proposal leaks private email address to reviewer email list

Since I have the "Hide my email addresses from other Launchpad users", I expected that Launchpad would not reveal my email address to other Launchpad users.

However, Launchpad sent an email impersonating me to the reviewer group email list when I created a merge proposal. There was no indication that this would happen.

Related issues:
- https://bugs.launchpad.net/launchpad/+bug/111147
- https://bugs.launchpad.net/launchpad/+bug/31586
- https://bugs.launchpad.net/launchpad/+bug/1098309

I'm surprised there isn't a unified email alias strategy here. For example, GitHub renders your email address consistently as "<numeric-ID>+<username>@users.noreply.github.com" if you have the equivalent "Keep my email address private" option checked.