If this is good for them, than why no marketing email feature a prominent unsubscribe button at the top of the email? Surely it's not an original idea by Google.
If you use something like MailChimp (I think that's what many new businesses tend to use? I can't remember..) or one with pretty subscribe/unsubscribe page for every customer who uses the mailing list service, then the customer's customers will have the luck to enjoy opt-in/opt-out option. If your organization is still running some out-of-date, custom subscription software, then unsubscribe might be out of the question.
