Hmm, triangulation is what happened to give Strava user's home location away with privacy zones. I also read the other day how multiple mics ("smart speakers" etc) can help locate someone's movement throughout a house. There's also smartphones who have infrared cameras on them like the CAT S60. And there's research where Bluetooth and WiFi can be used to assess if someone's home, and where their WiFi devices are located. Finally, I saw this picture with regards to 5G [1]. None of this is about AR glasses but I still thought it was interesting. Because the AR glasses part -even though AR isn't widespread- builds upon all of the above examples as input data.

[1] http://ictvietnam.vn/files/tccntt/source_files/2017/01/27/06...