Perhaps most controversially, the government believes it can “persistently” track the phones of “millions of Americans” without a warrant, so long as it pays for the information, a newly declassified report from the Office of the Director of National Intelligence, ODNI, reveals. Were the government to simply demand access to a device’s location instead, it would be considered a Fourth Amendment “search” and would require a judge’s sign-off. But because companies are willing to sell the information—not only to the US government but to other companies as well—the government considers it “publicly available” and therefore asserts that it “can purchase it.”
Here’ tge report (pdf): https://www.odni.gov/files/ODNI/documents/assessments/ODNI-Declassified-Report-on-CAI-January2022.pdf
Yeah, it’s the independent source exemption to the fruit of the poisonous tree doctrine, basically. The original data collection wasn’t illegal, as it was collected by a third party rather than the government, and so is admissable.