Update 11/20/2013: Read more at Engadget.
Coin has responded to people’s concerns about a waiter accidentally or intentionally selecting a different credit card.
One question we’ve been hearing is “What if a waiter/waitress accidentally — or worse, INTENTIONALLY — changes the card you want to charge your meal to?”
Here’s where Coin has you covered: The mobile app will allow you to configure an auto-lock feature that will disable the Coin button to toggle based on proximity; when the waiter walks away he or she will not be able to toggle the card selected.
I think there are better solutions but this one is adequate.
