Technologies with similar capabilities are being rolled out en masse throughout retailers across America. I've worked with a regional grocer supporting one of these projects. There are turnkey systems from several vendors, but the general concept is similar. Cameras have full coverage of the retail floorspace from multiple angles. The systems can track an individual throughout the store, and they can observe someone pulling items off the shelf.

This is used for a couple things. One, if customer pulls product A off the shelf instead of product B right next to it, the manufacturer of product B can purchase the ability to have their coupon print out at checkout to be handed to somebody who is proven to have an interest in the category. Alternately, it can be used with self-checkout systems to confirm that the shopper actually scanned product A, or to alert security to check the shopper's receipt and cart at exit.

Amazon is offering this sort of technology for checkout-less stores, but similar offerings for loss-prevention and targeted marketing are online and available.

It would be trivial to add face recognition to this stack, and I strongly suspect it is in fact offered if you ask for it. The use case there would be focused around the loss prevention aspect, and that's a huge financial driver for implementing these systems.

Another interesting feature of this market is that the websites for the products themselves don't really advertise the full functionality of the product. You won't see the scale of the offering until you get to the in-person sales demo and slide decks. It feels like the vendors know how the technology could be perceived.