Warn them and give them a link to unsubscribe easily, but don't miss out on the opportunity to collect a single data point on why they are unsubscribing (checkb

Warn them and give them a link to unsubscribe easily, but don't miss out on the opportunity to collect a single data point on why they are unsubscribing (checkboxes or buttons for 'Didnt use it', 'Didnt find it useful', 'Too expensive', 'Buggy', etc...)