There was an article here a few weeks ago about how these surveillance companies then sell this information to US law enforcement agencies. Though the governmen

There was an article here a few weeks ago about how these surveillance companies then sell this information to US law enforcement agencies. Though the government would need a warrant to compel these companies to turn over this information, they have decided they don't need permission to buy information on the public market. A free market surveillance state is acceptable. No clue if this presentation covers this, as the video is still unavailable.