Chick-fil-a has this.
One of the tech people there was on HN a few years ago describing their system. Credit card approval slows down the line, so the cards are automatically "approved" at the terminal, and the transaction is added to a queue.
The loss from fraudulent transactions turns out to be less than the loss from customers choosing another restaurant because of the speed of the lines.
Credit card information would be recorded by the POS, synced to a mini-server in the back office (using store-and-forward to handle network issues) and then in a batch process overnight, sent to HQ where the payment was processed.
It wasn't until chip-and-PIN was rolled out that they started supporting "online" (i.e. processed then and there) card transactions, and even then the old method still worked if there was a network issues or power failure (all POSes has their own UPS).
The only real risk at the time was that someone tried to pay with a cancelled credit card - the bank would always honour the payment otherwise. But that was pretty uncommon back then, as you'd have to phone your bank to do it, not just press a button in an app.
