On June 22, 2018, the United State Supreme Court decided the case of Carpenter v. U.S. Chief Justice Roberts authored the 5-4 majority opinion. The principal issue was whether a warrant is required to obtain a mobile phone user’s cell-site information.
The Chief Justice held in relevant part as follows: Cell phones perform their wide and growing variety of functions by continuously connecting to a set of radio antennas called “cell sites.” Each time a phone connects to a cell site, it generates a time-stamped record known as cell-site location information (CSLI). Wireless carriers collect and store this information for their own business purposes.
Here, after the FBI identified the cell phone numbers of several robbery suspects, prosecutors were granted court orders to obtain the suspects’ cell phone records under the Stored Communications Act. Wireless carriers produced CSLI for petitioner Timothy Carpenter’s phone, and the Government was able to obtain 12,898 location points cataloging Carpenter’s movements over 127 days—an average of 101 data points per day. Carpenter moved to suppress the data, arguing that the Government’s seizure of the records without obtaining a warrant supported by probable cause violated the Fourth Amendment. The District Court denied the motion, and prosecutors used the records at trial to show that Carpenter’s phone was near four of the robbery locations at the time those robberies occurred. Carpenter was convicted. The Sixth Circuit affirmed, holding that Carpenter lacked a reasonable expectation of privacy in the location information collected by the FBI because he had shared that information with his wireless carriers.
The argument that there is “no reasonable expectation of privacy” information that one “chooses to share” becomes weaker with each passing day. Modern business practices essentially require most people to carry smart phones that track their locations. I know of just one employed adult that does not carry a smart phone that s/he uses for business purposes throughout the day. He is a fireman that routinely checks his home phone’s voice messages from the landline at his firehouse.
