Sometimes, simpler is better. Dan Solove has generated an interesting test that the Supreme Court could apply to determine if GPS surveillance should require a warrant:
The Fourth Amendment applies to a surveillance technology used in public if the surveillance technology: (1) extends significantly beyond human capabilities; and (2) is used in a manner beyond its ordinary use by the general public.
Read Dan’s thinking about why this would be a useful test on Concurring Opinions while I mull this over some more. My first thought is, “Why stop there? Why not write the test in a way that it also applies to requests for prospective cell location data?” Why not say, “The Fourth Amendment applies to the use of technology or digital data held by third parties if a significant purpose of its intended use is surveillance and its use: (1) extends significantly… etc.”
But then I channeled Orin Kerr, and could already hear his arguments. 🙂