Legal Commentary

Cell Phones, Magic Boxes, and the Fourth Amendment

By Orin Kerr

The results of the reader poll on how cell phones work were quite startling: With over 1,600 votes cast, the results indicated that 95% of those who answered the poll know that cell providers get location information. Only 5% didn?t know that. Of course, Volokh Conspiracy readers aren?t typical: They have the intelligence and sophistication to visit here. Plus, it makes sense that the poll would over-represent readers who know of such things. All things being equal, you?re more likely to answer a poll if you know what it?s talking about than if you don?t. Still, the numbers were surprisingly lopsided.

The reason I asked, as some have figured out, is that one of the legal issues that arises in whether the Fourth Amendment protects cell-site data is whether users know that the information is transmitted. My own view is that as a matter of law, courts should assume that users of a technology understand the technology when the courts apply Fourth Amendment law to it. The Constitution shouldn?t safeguard ignorance, and even if it did, improving understanding over time means that any rule based on ignorance has a limited shelf-life. Further, past Supreme Court cases have presupposed understandings of the technology: In Smith v. Maryland, for example, the Court presupposed that people know how telephones work when there wasn?t actually any evidence in the case that this was true.

But even if you don?t agree with me this, it?s just interesting to get a sense of what different users know about what information cell phones reveal. Some courts have concluded that reasonable people don?t know how cell phones work, and that they are sort of a magic box that secretly gives away location information. They haven?t offered any empirical support for this view: It is just offered as a guess of what reasonable people think. My intuition is that this guess closely matches what the judge thought before the judge had the case: If the judge saw the technology as a magic box, then that is how a judge will conclude a reasonable person would think about it. What?s interesting to me is that the VC readers who answered the poll don?t see cell phones as magic boxes. Instead, they overwhelmingly know how cell phones work.

Full post as published by The Volokh Conspiracy on November 08, 2010 (boomark / email).