My naive suggestion. "Hard" unsubscribe button that tosses all future emails from this list in the trash and mails the sender a note that the address has unsubs

My naive suggestion. "Hard" unsubscribe button that tosses all future emails from this list in the trash and mails the sender a note that the address has unsubscribed from this list and all future emails will be ignored. Gmail has over a billion active users. Mailing lists will probably adapt to whatever crumbs Google leaves on the doorstep.