Description
When the merchant taps checkout, we prime the card reader for payment.
If they stay on that screen even after a customer leaves and decides they don't want the purchase, the card reader can stay ready for payment for a long time.
The reader uses more battery when it's ready to take payment, and there's a small risk that another shopper might pay for the wrong order, if they see the "tap card" instruction on the reader when they get to the till.
Stripe has a 30 minute (or more) time out, but that seems excessive – let's consider adding a 2-5 minute time out instead.