(commenting here since previous discussion is now archived...)
It looks like you may have predicted the latest FBI maneuver here. The FBI is now claiming to have paid a professional hacker group for the technique, not Cellebrite. Maybe they realized the possible legal exposure after reading your comments? The FBI is looking awfully incompetent when armchair lawyers are a step ahead of them.

From the paper, it looks like this technique requires significant cooperation from the client. The client must put the wifi card in monitor mode and use a proprietary protocol to blast across the spectrum for 28ms (which pauses all traffic on the AP also). Also, the client needs to have 3 antennas spaced 12-30cm apart. Maybe some laptops and tablets have such a builtin antenna array but definitely not mobile phones or watches.

I doubt this will begin tracking people without their knowledge. It's still very interesting and I hope to use it on some robotics projects but it won't ever become a passive consumer monitoring system. If we start to see 6 antenna APs and big 3-antenna phone cases, then I'll become suspicious...

"This is all part of the move away from legacy single-user design crap..."

Part of the reason that Windows is still buggy and a pain to administrate is because multi-user requirements are continually being shoehorned into a single-user OS. The NT team had some fundamental assertions: single user, graphics drivers in user space. Most of today's problems are because those assertions have been grossly violated by subsequent versions of Windows.

It also ignores reflexes and experience. A twitchy teenager has a much better chance of beating grandma to the draw. An experienced gunman beats a novice in a stressful situation.

A fully armed society doesn't level the force playing field, it just changes the skill sets involved.