I am not a major fan of recurring transactions that can pull from my balance without my conscious agreement each time, but I understand that a lot of folks really like that convenience. I wonder if there would be a way to have a NIP-46 style signer for payment requests, so I could decide if I want to sign only a particular single request for payment, or I could tell it to approve all such requests from a particular source, and I could revoke that permission at any time.