> there are companies such as Cognitive
It's my understanding that there have been companies trying to sell solutions like this for people-tracking indoors for supermarkets/grocery stores, shopping malls, large department stores for at least 7-8 years now.
(edit: Stuff like RF beacons built into shopping cart handles, right? Since the shopping carts are centrally owned/managed/controlled and with unique serial numbers, and mostly don't get stolen or leave the property.)