One of the most important privacy battles of this young century plays out today in a Philadelphia court room when lawyers for CDT, EFF, and the ACLU will argue that a federal appeals court should uphold a lower court ruling  stating that law enforcement needs a search warrant (based on "probable cause") before being allowed access cell phone location information. Government lawyers, however, will argue that law enforcement doesn't need a search warrant and only needs to prove that there are "reasonable grounds" to believe that the data is relevant to their case. The probable cause standard for a search warrant is much more rigorous and privacy-protective.
In writing her original opinion , U.S. Magistrate Judge Lisa Lenihan said that "citizens continue to hold a reasonable expectation of privacy in the information the government seeks regarding their physical movements/locations" and that such information is "protected by the Fourth Amendment's warrant requirement." To allow the lower standard for access that the government is asking for makes that information "particularly vulnerable to abuse," Lenihan wrote.
So, what's at stake here? If the appeals court sides with the government lawyers, "it will run headlong into serious constitutional questions affecting the rights of every cell phone user," says the brief  filed by CDT, EFF and the ACLU.
The Justice Department thinks otherwise. The DoJ brief says that, according to its interpretation of the current law, although you "may well prefer to keep [your] whereabouts confidential," when you use a cell phone you essentially have "no right to privacy" for the tracking information being logged on your mobile phone. Why? The DoJ says this is because you "voluntarily" disclose that information to your data carrier the moment you fire up your cell phone. "Thus, [the user] assumes the risk that his cell-site usage may be disclosed to law enforcement," the DoJ brief says.
And just to round things out, the Justice Department offers up this no muss, no fuss solution to this privacy quagmire: "One who does not wish to disclose his movements to the government need not use a cellular telephone." No, I'm not making that up.