The 4th Circuit Court of Appeals upheld what is known as the third-party doctrine: a legal theory suggesting that consumers who knowingly and willingly surrender information to third parties therefore have “no reasonable expectation of privacy” in that information — regardless of how much information there is, or how revealing it is. Research clearly shows that cell-site location data collected over time can reveal a tremendous amount of personal information — like where you live, where you work, when you travel, who you meet with, and who you sleep with. And it’s impossible to make a call without giving up your location to the cellphone company. “Supreme Court precedent mandates this conclusion,” Judge Diana Motz wrote in the majority opinion. “For the Court has long held that an individual enjoys no Fourth Amendment protection ‘in information he voluntarily turns over to [a] third part[y].
Daniel Solove’s work forms the basis of our recent analyses of big data privacy. It is impressive that he pulls together a comprehensive analysis of the implications of the passing of Justice Scalia for the third-party doctrine within a day. Justice Scalia’s opinion in Jones actually provides very little protection against government location tracking. Only the physical affixing of a GPS device to a car violates the 4th Amendment according to his view. But under the third party doctrine, the government can readily obtain GPS data from third parties that provide GPS services without a physical trespass to the car.