It’s the “within their reach” that constitutes the targeting, it seems to me. Maybe “particularized scrutiny” is a better word?

Each fancy radio can only be in one place at one time, and presumably with a human operator in the vehicle or wearing the backpack. Which emulates a cell station, not all tens of thousands of them in the state simultaneously.

That feels much more like “DUI checkpoint checking all cars on this road at this time,” or “canvassing the neighborhood around the crime,” or “the stadium operator invited the cops into the security office to watch their CCTV feeds during the big game.” Precipitated on some reason—maybe not the specific human, but something that’s different about that place and time that warrants a human targeting their attention there.

As opposed to the network-level, “all communications between all people all the time just in case” that constituted the “mass” surveillance that Snowden described (and Flock has since innovated and extended to the physical world).