This shit again? The FUD here always implies the technique is like what we see in (((movies))). The truth is that all it can really do is detect the presence of an individual but not identify them. This is not a detailed optical camera by any means and is more akin to a thermal imager but with even lower resolution. These are better ways of surveilling people inside a dwelling so being afraid of your WiFi is just the thing that they want to convince gullible people that they are being watched so that you'll police themselves. You already carry a tracking device so who gives a fuck if you can see a blob that represents the body that wears the tracking device?
It can detect (specific) people and -most- actions they are doing at any given time based on a few methods now. I have seen a (not public) system do this. I cant mention which because of NDA but it's way better than you think it is.
If trained with several people it can probably differentiate between them, but only in the same way that your bathroom scale can tell who's standing on it.