[sc_rufctr]

The cashier should've mentioned the charge before adding the tip to the bill so I agree with the reverse charge. At some point you will probably have to pay for the meal but maybe they'll learn something.

Having said that... A while ago I went to a restaurant with my GF. I paid using my credit car and a few days later noticed that charge hadn't appeared on my bill. I then checked the receipt & only then did I notice that the payment hadn't gone through (communication error). So I called the restaurant, explained what had happened and paid over the phone. The bill was about $160 total.

They didn't know anything about me so I had the option of doing nothing but that would have been dishonest IMO (even though it was their mistake).