In a previous post, we discussed the test that the Supreme Court will likely use to resolve United States v. Carpenter, the major Fourth Amendment case that will be argued in the Supreme Court tomorrow. We responded to Orin Kerr’s argument that the Supreme Court should not consider people’s actual expectations of privacy in resolving Carpenter. In this post, we will examine Orin’s proposed alternative test and discuss the state of public knowledge about cell phone location tracking.

In Orin’s recent blog post, he discusses the connection between people’s knowledge of cell phone technology and their expectations of privacy in their cell phone’s location. Each of the appeals courts to examine the constitutionality of historical cell phone location tracking has based its decision in part on the extent of societal knowledge about cell phone technology. Controversially, most of these courts, including the Sixth Circuit in Carpenter, have concluded that cell phone users are generally aware that their cell phone companies are tracking their locations and storing records of their movements. This is a somewhat remarkable claim regarding public knowledge of an obscure and complex location tracking technology—and empirical surveys of cell phone users suggest that it is mistaken.

One of us has recently conducted a large-scale survey indicating that Americans are overwhelmingly not aware that their cell phone providers collect location information on them via their cell phones. Indeed, most people do not seem to be aware that their movements can be tracked using their cell phone signals. Accordingly, they do not knowingly disclose information about their movements to third parties.  Nor do they consent to such disclosure, because one cannot consent to something unconsciously or unknowingly.

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