From Brendan I. Koerner’s “Your Cellphone is a Homing Device” (Legal Affairs: July/August 2003):
Law enforcement likewise views privacy laws as an impediment, especially now that it has grown accustomed to accessing location data virtually at will. Take the MetroCard, the only way for New York City commuters to pay their transit fares since the elimination of tokens. Unbeknownst to the vast majority of straphangers, the humble MetroCard is essentially a floppy disk, uniquely identified by a serial number on the flip side. Each time a subway rider swipes the card, the turnstile reads the bevy of information stored on the card’s magnetic stripe, such as serial number, value, and expiration date. That data is then relayed back to the Metropolitan Transportation Authority’s central computers, which also record the passenger’s station and entry time; the stated reason is that this allows for free transfers between buses and subways. (Bus fare machines communicate with MTA computers wirelessly.) Police have been taking full advantage of this location info to confirm or destroy alibis; in 2000, The Daily News estimated that detectives were requesting that roughly 1,000 MetroCard records be checked each year.
A mere request seems sufficient for the MTA to fork over the data. The authority learned its lesson back in 1997, when it initially balked at a New York Police Department request to view the E-ZPass toll records of a murder suspect; the cops wanted to see whether or not he’d crossed the Verrazano Narrows Bridge around the time of the crime. The MTA demanded that the NYPD obtain a subpoena, but then-Justice Colleen McMahon of the State Supreme Court disagreed. She ruled that “a reasonable person holds no expectation of confidentiality” when using E-ZPass on a public highway, and an administrative subpoena – a simple OK from a police higher-up – was enough to compel the MTA to hand over the goods.