Detecting Restaurant Credit Card Fraud with Checksums
Clever technique to put a checksum into the bill total when you add a tip at a restaurant.
I don’t know how common tip fraud is. This thread implies that it’s pretty common, but I use my credit card in restaurants all the time all over the world and I’ve never been the victim of this sort of fraud. On the other hand, I’m not a lousy tipper. And maybe I don’t frequent the right sort of restaurants.