I recently noticed (by looking at code) that since the format of the email set command changed from

set <option> {on|off} <password>

to things like

set authenticate <password> set <option> {on|off}

in going from Mailman 2.0.x to 2.1, Mailman.Utils.is_administrivia() was never updated to account for the new formats, and therefore, valid set commands are never recognized as administrivia.

I filed a bug at https://bugs.launchpad.net/mailman/+bug/796836.

Please see the last paragraph of the bug report and let me know if you have an opinion.