I would be in favor of a different approach: a merchant should not, under any circumstances, be able to remove money from an account, charge a credit card, or otherwise take money from someone without the explicit authorization of the customer. In this context, explicit means one of two things:

1. The customer intentionally authorized that specific transaction. A specific transaction means one transaction. If a merchant wants to use this approach, they need to ask for authorization each time they charge.

2. The merchant may register a subscription or other recurring charge arrangement with the customer’s bank or card provider. The customer must explicitly authorize this registration at the time it occurs and may, by contacting their bank, revoke the authorization at any time. The merchant may not recreate the authorization without the customer re-authorizing it at the time of creation.

Eventually, the whole pull model of money transfers needs to go away. Taking money from someone by knowing their account number is nonsensical and should not be possible.