It really depends on how the email list back end is set up. For the short period of time that I used MailChimp for a small nonprofit, we didn't have an automated remove feature (I had a link that generated a web page that said unsubscribe successful, and then on the back end, an email was generated and sent to me informing me of such, and I'd have to manually go in and scrub. It was just a monthly newsletter so I didn't automate anything, I mainly used MailChimp for statistics)

I'd imagine that you and others with a large web presence such as Lucky would have an automated system in place to allow people to unsubscribe themselves (where the system would automatically scrub their email address from the list). But the key point here is the assumption that it works. If there's any sort of error where the recipient isn't successfully unsubscribed, or the unsubscribe link is deceptive in where it only unsubscribes from one type of email but not others, MailChimp doesn't care, you're now a spammer in their eyes.