It's a numbers game once they subscribe, even if the link is there. Some people, myself included, won't hit that unsubscribe button. I'll just forever mark it as spam until it no longer shows up in my inbox.
Instead, just add filters to drop everything from the email sender.
Or if you're like me, make an auto-responder that's directs to their CEO's inbox telling them to "Fuck Off Spammer". (I actually do this)