[seriousquestion]

How does that work? How do they get the ID? And is it location accurate enough that it would not get confused with another phone a few feet away?

[mikem170]

Wifi and/or bluetooth media addresses, which are unique. I've heard that wifi tracks you to the store, bluetooth to the aisle in the store. A lot of people have all this enabled on their phones, right? Then there's the apps installed on so many phones that are built using facebook sdk's and similar that include a lot of spyware.

I have the impression that stores doing this are working with data aggregator to associate this information with other sources of info, like credit card purchases, facial recognition, phone number and imei, etc.

[duderific]

> I've heard that wifi tracks you to the store, bluetooth to the aisle in the store.

I interviewed a guy who worked on this very technology. It's used in retail stores to track foot traffic and how people move around the shopping area.

[notdang]

Android and iOS are randomizing the mac addresses.

[throwdecro]

If they do this to a person from an EU country, won't that person have a potent issue to raise via GDPR?