You could do it without the need for centralised party. Banks could issue a cancel notice i.e. a webhook/something to poll that says "this card will no longer b

You could do it without the need for centralised party. Banks could issue a cancel notice i.e. a webhook/something to poll that says "this card will no longer be honoring this subscription". That way users can cancel in our bank app... potentially right next to where we see the line item, and will have the protection of the bank being the one who does so (vs a user clicking something on their site).