Why would the expectation of privacy be different depending on which spectrum of light the information was captured in (visible vs radio)?
In both scenarios, the data is held by a private third party and a person generates this data pretty much by-default.
This is the relevant bit:
In Carpenter, this Court held that accessing cell-site location
information (CSLI) constitutes a Fourth Amendment search because
“individuals have a reasonable expectation of privacy in the whole of their physical movements,” 585 U. S., at 310. The Court reasoned that CSLI provides a “detailed” and “encyclopedic” portrait of a person’s whereabouts, id., at 309, and, with that, “an intimate window into a person’s life,” id., at 311. Because people “compulsively carry” their cell phones “all the time,” the Court explained, a cell phone “tracks nearly exactly the movements of its owner,” and thus “faithfully follows” him not only through “public thoroughfares [but] into private residences, doctor’s offices, political headquarters, and other potentially revealing locales.”