I have a user with an email address that bounces constantly with Amazon SES and they refuse to change it. If I disable it as admin, they turn it back on. The user claims he is getting email but Amazon SES sends clear non delivery messages, and Discourse logs mail as bounced, so there is something very (emphasis on very) weird going on, but that is a separate matter.
Is there a way to turn off mailing list mode for a given user in such a way that it cannot be enabled again? I want to do this until the user in question responds to polite requests to use an alternate email address.