Hi Jason,
as far as I am concerned, in most countries today it's a requirement to double opt in when subscribing to something, i.e newsletters, digests, etc... So users in general should be aware what they are subscribed to, so stuff like "well, you bought something from us like two years ago, so we take it for granted to spam you with our new and fancy marketing engine now" should be easily seen as spam. However, saying "should be aware" also means that users keep forgetting, or are not aware they have subscribed to a newsletter, i.e. because the sender tricket them into double opt in by having the shipping address confirmed, where the answer is also a confirmation of a subscibtion to a newsletter.
The other point, as you already mentioned, is that users are now unwilling to hit the unsubscribe link, which in my eyes is actually a great development, as it shows that people finally getting educated not to click on every link they see. However, I don't think the solution you are suggesting should be used, as in my opinion it makes the problem only worse. Think about it, once a user clicks on a fake unsubscribe link, this means the spammer gets a confirmation of a working email address. And that's what they are after, it does not matter that you'll report this message as spam later, because by the time you do - most likely after two or three days - these "unsubscribe-campaigns" will already be over. They are working with the time spam most users expect to get unsubscribed from a newsletter - unfortunately this is even common practice with valid newsletter issuers, when they declare to "give us one week to process your unsubscribe request".
So, my suggestion would be to give the users the opinion to react to messages with unsubscribe link the way they think it's best for them - if they are somehow familar to to the issuer - use the unsubscribe link. If the message sells blue pills or Casino Credits, don't bother with any links, just report it as spam. If the content is reasonable and professional, but the user has simply no realationship to that company, then flagging it as marketing would probably the best way to go. Makes of course only sense if you are using some kind of marketing filtering or flagging.
Just my two cents on that.
Cheers, Andreas
