> Technology to track individual customers through the store based on smartphone RF is already deployed in many supermarkets.

Phones have been randomizing and rotating MAC addresses for a long time. With enough antenna arrays you could theoretically track an individual RF source through the store but you wouldn't be able to tie it to a returning customer or identity by itself.

The days of easy external phone tracking are long over.

Your scenario is more than just a software update and dotting some i's. Pulling this off would require a lot of hardware and compute.

The best you could do is force everyone to scan prices through their phone with an app registered to them. You probably won't have many customers left when everyone gets tired of pointing their phone at everything to see their custom price.

You're already watched by security cameras, it's not hard to do facial recognition anymore. And you have companies literally lining up to sell such facial recognition databases. It's conceivable they could determine what price you pay for groceries while your car is on the way to the store, thanks to Flock.