While disposable numbers are a good idea, that is entirely orthogonal to my proposal. What I’m talking about is using the accept/reject on a credit card transaction as a way to communicate one bit of information back to you — “this store has a bad enough reputation that you probably don’t want to shop here.” You could do that with a disposable number or a reusable one as you wish. The disposable numbers were primarily intended for online shopping, and I still contend that a browser plugin is probably a better way to be warned about shady web shops, though the idea of forcing people to rate merchants when examining the credit card bill remains valuable either way.

Disposable numbers really never worked for brick and mortar purchases.

This method would also not work for restaurants or other places where you use the card after you’ve consumed your purchase. As such it would probably never reject a purchase from such establishments, and just tell you after the fact you made a mistake in case you are planning to repeat it. (ie. an E-mail that night saying, “Before you go back to eat again at Mia Botulisma you might want to know something…”)

This idea relates to one of the first ideas I posted on this blog, the big yellow button.