Way to go Michael, it really pays to read the "Note:..."!
Brian, there goes my idea to put a 29MP over every cash register at Walmart...
The PCI Data Security Standard (DSS) specifically excludes the need to provide cameras over cash registers:
DSS 9.1.1: "Use video cameras and/or access control mechanisms to monitor individual access to sensitive areas. Review collected data and correlate with other entries. Store for at least three months, unless otherwise restricted by law. Note: - Sensitive areas refers to any data center, server room, or any area that houses systems that store, process, or transmit cardholder data. This excludes the areas where only point-of-sale terminals are present, such as the cashier areas in a retail store."
Funny, because if anything I've heard data that could suggest the exact opposite. Super hi-res cameras over registers run the risk of recording credit card numbers if a shopper hands their card over to the cashier (for swipe, signate inspection, etc.). Not sure if it's a an actual problem, or just folklore, but it runs a little counter-intuitive to requiring a camera over every register (which, to me, implies wanting to decent decent shots with some detail).