Nothing stopping them doing that the other way either.
I run a newsletter where both subscribe and unsubscribe do double-opt-in (i.e., both subscribing and unsubscribing send you an email with a confirmation URL with a token - each newsletter has an unsubscribe link but that link doesn't include the token). Maybe this is a mistake? Is the norm that anyone can unsubscribe anyone else from newsletters?
Just use mailto links in List-Unsubscribe.
List-Unsubscribe: <mailto:list@host.com?subject=unsubscribe>
It's convenient, standardized and removes the need for further confirmation because you know who sent the mail.
That said, I don't see what the big deal is. If you forward a newsletter issue in its entirety to someone else, they hate it and feel confused enough about receiving it to click the unsubscribe link, maybe the sender deserves being unsubscribed. The absolute most you should do at this point IMO is to notify them that they were unsubscribed.
> Just use mailto links in List-Unsubscribe.
List-Unsubscribe is not widely enough adopted to be the only means of unsubscription (yet): https://news.ycombinator.com/item?id=23360654
> maybe the sender deserves being unsubscribed
That's super presumptive/rude. Also not how interactions between people work, at all. The potential consequences of a mistaken forward-unsubscribe are also often quite large: https://news.ycombinator.com/item?id=23360619
I am not suggesting List-Unsubscribe as the only means of unsubscription. Read my post again. It also is widely adopted. gmail.com, Mail (OSX, iOS) and outlook.com together probably represent the majority of clients now and all support List-Unsubscribe.
> That's super presumptive/rude. Also not how interactions between people work, at all. The potential consequences of a mistaken forward-unsubscribe are also often quite large
Maybe my view on the matter is colored by the fact that my friends and family don't send a bunch of useless marketing to me, and I have the decency not to send them any. Still, my suggestion solves the problem if you have it without involving a convoluted process to cancel a subscription. I absolutely could not care less about the dire consequences of not receiving a steady stream of cosmetics coupons, but whatever floats your boat, email-based unsubscribe works.
https://www.telemedicus.info/urteile/Wettbewerbsrecht/Werbun...
That term is super widely used in spam-prevention, commercial email sending, transactional email sending, and inbox provider industries.
You can disagree with the phrasing if you want, but that doesn't make it propaganda--not any more than the Orwellian naming of the "No Child Left Behind" act makes the law itself propaganda.