I don’t mean to speak for him, but I believe what he’s saying is that if they can’t track us with flock cameras, they’ll just do it by reading our TPMS sensors as we drive down the street

TPMS "Tire Pressure Monitoring System" is federally mandated (49 CFR § 571.138).

In many TPMS implementations, each tire has a sensor which broadcasts a short range signal to the ECU. Those signals include sensor identifiers (sent in the clear) so the ECU knows which tire is low.

Those signals can be picked up from 50m away. A set of 4 identifiers can (typically) be mapped to a specific car.