I have a simple rule for email that I don't want. If there is a way to easily opt-out (clicking a link, replying with "unsubscribe", or (in rare cases) filling out my email address on a form) I will do that. I should also set a rule for that sender saying "opted-out" so I can know if they aren't respecting that. If I can't do any of those things, I mark it as spam and move on. I don't care about the negative impact to your future emails by getting spam reports in Gmail. It doesn't concern me. Let me unsubscribe easily and legally.