Yep - that’s the major leak. Bluetooth and potentially the cellular radios are also likely vectors of exploitation. This has been going for a while now, long enough for there to be a whole industry around it targeting brick-and-mortar retailers with buzzwords like “foot traffic analytics”, “geofencing”, “1:1 marketing” and “emotional connection”. (the same retailers of course who are now desperate to find techniques to compete with AdWords, Amazon, et al and their online analytics omniscience).
Somehow find it not comforting at all that a major retail backer of one of the bigger players, is Louis Vuitton - (what with their track record and all). An aspect that isn’t mentioned in the article is that when these sensors systems are networked and if they are sufficiently dense they function as non-GPS dependent localizers which can trivially interpolate routes traveled, and of course there is no opt-out option.
