The One-Click Unsubscribe-function poses a problem. If a contact assosciated with several subscribtion types, the One-Click Unsubscribe only unsubscribes the corrosponding email-subscription, from which the clicked through.
There’s no way to receive a report or any warning of this, so that an automated process to unsubscribe all subscription types can be set up.
The One-Click Unsubscription Explanation is called RFC 8058, and there should be a property or something under Subscriptions History so that a warning system could be automated.