You do know how this happened right? Wifi SSIDs with similar strengths reveal if people are in the same area, then just correlate timestamps and viola!
I wouldn't throw the elder person under the bus on this one, the tactics are sophisticated, and honestly, just a precursor to what will happen with AR.
To give a bit more of how it's implemented (at least how I would propose it in iOS), Insta/FB/Whats queries available wifi SSIDs as a background process (or whatever they have for notifications/networking etc), and does the same to your therapist since you both have insta / fb / whats ... and based on the signal strength, can say with confidence you two were in the same room because XYZ Wifi strength is -Xdb just like yours (walls are strong signal augmenters), and you are both there for some time based on the background thread timestamp.
I wouldn't throw the elder person under the bus on this one, the tactics are sophisticated, and honestly, just a precursor to what will happen with AR.
To give a bit more of how it's implemented (at least how I would propose it in iOS), Insta/FB/Whats queries available wifi SSIDs as a background process (or whatever they have for notifications/networking etc), and does the same to your therapist since you both have insta / fb / whats ... and based on the signal strength, can say with confidence you two were in the same room because XYZ Wifi strength is -Xdb just like yours (walls are strong signal augmenters), and you are both there for some time based on the background thread timestamp.