So. Their security cameras, that are literally everywhere in the store? they’re tied into all sorts of biometrics. Facial recognition, gate recognition.
They also get your name, address, etc, if you ever use a credit or debit card, and match it to that. Their system goes and dives and runs everything public about you, as well as they record everything you do, everything you buy, and build that into a dossier. Their loss prevention staff, get alerts about anyone they think needs to be watched.
pretty much all of the big box stores and other large retail chains are using these kinds of systems. hell, Some places have started using “smart” cameras to track how long you stare at the gossip rags while waiting to check out, or the candy as you walk by the candy aisle.