Yeah, don't add this here.

My vote is to not have the backdoor stuff in `settings.py` at all. Instead, add it to `settings_local.py-dist` commented out with a big comment above it saying, "If you're doing development work and you're not in production and you have no Internet connection, uncomment the following and set `BROWSERID_AUTOLOGIN` to the email address of the account you want to log in as."

This is a pretty specific situation that's very particular to development, so I think it's ok to not have it in settings.py at all.