An upcoming law review article highlights the “missed opportunity” presented by the Jones GPS tracking case:  It’s Raining Katz and Jones: The Implications of United States v. Jones – A Case of Sound and Fury by Professor Jace C. Gatewood, Atlanta’s John Marshall Law School

The article has a title that is too cute – both a pun and a Faulkner reference! – but is worth a read.

Professor Gatewood notes that Jones “did serve to highlight a previously glossed-over privacy issue — whether there is a privacy interest in the sum total of one’s movements.”  He concluded:

Though Jones dealt exclusively with GPS technology, which is capable of generating “a precise, comprehensive record of a person’s public movements that [may] reflect[] a wealth of detail about familial, political, professional, religious, and sexual associations,” other technologies, including Smartphones, manufacturer GPS-equipped vehicles, license plate scanners, and roadside video cameras, to name a few, all may be used in a similar manner to track and record isolated instances of an individual’s movements, which then can be stored and later aggregated to create a unique profile of an individual’s movements, and which can reveal personal information in a way not previously considered.

Professor Gatewood refers to this as the “mosaic effect.”  in a law review article written before the Jones decision, I had indicated my disagreement with this characterization, noting that the D.C. Circuit’s opinion in Jones case did “not represent a significant departure from traditional Fourth amendment jurisprudence in favor of a mosaic theory. . .” as some have suggested.  See JA Engel, Courts Re-Examine The Application Of Goldfinger era Electronic Tracking Cases To Law Enforcement Use Of GPS Tracking Devices, 14 RICHMOND J. OF LAW AND THE PUBLIC INTEREST, 401, 416 n. 109 (2011).)  This post from July also highlights the mosaic issue.

I think this observation from the article is mostly correct:

Ultimately, with each new advancement in technology will come even greater and more precise methods of recording, storing and aggregating information in a manner that may be later used to determine, with particular detail, how we travel, what we buy, what we read, who we visit, and so on. No physical intrusion of any kind will be necessary to many forms of these technologies, and some may even become so common-placed we may just accept the loss of privacy that comes with the convenience. Yet still other technology may be used to record only isolated pockets of information comparable to visual observation so as to be unobjectionable.

While I agree that the trespass test used to decide Jones has very limited value in evaluating these cases, my view remains that the two part Katz test is adequate to evaluate these cases.  This test asks whether there has been an invasion of a subjective expectation of privacy, and whether that expectation of privacy is objectively reasonable.