The technology to convert wifi signals into the placement and identity of people is getting much better. Not by using their devices, just the waves bouncing of their bodies. (There’s nothing new to the pipeline as far as I can tell, we’re just starting to get into the accuracy ranges that make it easy/useful.)
To an extent. it’s better to have it inside with you and lots of other devices around to get a good picture from the BFI.
AS bad as it sounds, you’r probably sitting next to, or carrying with you a cellphone with a unique IMEI that ties you to credit cards and social security numbers, it has an exact GPS lock available to police for the asking, and even if you turn that off, a yagi or any antenna locator could id you far better than the BFI.