CSLI is a mere business record subject to the third party doctrine and accessible without a warrant. United States v. Carpenter, 2016 U.S. App. LEXIS 6670 (6th Cir. April 13, 2016) (two articles at end of quote):
In Fourth Amendment cases the Supreme Court has long recognized a distinction between the content of a communication and the information necessary to convey it. Content, per this distinction, is protected under the Fourth Amendment, but routing information is not. Here, Timothy Carpenter and Timothy Sanders were convicted of nine armed robberies in violation of the Hobbs Act. The government’s evidence at trial included business records from the defendants’ wireless carriers, showing that each man used his cellphone within a half-mile to two miles of several robberies during the times the robberies occurred. The defendants argue that the government’s collection of those records constituted a warrantless search in violation of the Fourth Amendment. In making that argument, however, the defendants elide both the distinction described above and the difference between GPS tracking and the far less precise locational information that the government obtained here. We reject the defendants’ Fourth Amendment argument along with numerous others, and affirm the district court’s judgment.
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In the twentieth century, the telephone call joined the letter as a standard form of communication. The law eventually followed, recognizing that police cannot eavesdrop on a phone call—even a phone call placed from a public phone booth—without a warrant. See Katz, 389 U.S. at 352-55. But again the Supreme Court distinguished between a communication’s content and the information necessary to send it. In Katz, the Court held that “[t]he Government’s activities in electronically listening to and recording the petitioner’s words” was a search under the Fourth Amendment. Id. at 353 (emphasis added). But in Smith, the Court held that the police’s installation of a pen register—a device that tracked the phone numbers a person dialed from his home phone—was not a search because the caller could not reasonably expect those numbers to remain private. “Although [the caller’s] conduct may have been calculated to keep the contents of his conversation private, his conduct was not and could not have been calculated to preserve the privacy of the number he dialed.” Smith, 442 U.S. at 743 (emphasis in original).
Today, the same distinction applies to internet communications. The Fourth Amendment protects the content of the modern-day letter, the email. See United States v. Warshak, 631 F.3d 266, 288 (6th Cir. 2010). But courts have not (yet, at least) extended those protections to the internet analogue to envelope markings, namely the metadata used to route internet communications, like sender and recipient addresses on an email, or IP addresses. See, e.g., United States v. Christie, 624 F.3d 558, 574 (3d Cir. 2010); United States v. Perrine, 518 F.3d 1196, 1204-05 (10th Cir. 2008); United States v. Forrester, 512 F.3d 500, 510 (9th Cir. 2007).
The business records here fall on the unprotected side of this line. Those records say nothing about the content of any calls. Instead the records include routing information, which the wireless providers gathered in the ordinary course of business. Carriers necessarily track their customers’ phones across different cell-site sectors to connect and maintain their customers’ calls. And carriers keep records of these data to find weak spots in their network and to determine whether roaming charges apply, among other purposes. Thus, the cell-site data—like mailing addresses, phone numbers, and IP addresses—are information that facilitate personal communications, rather than part of the content of those communications themselves. The government’s collection of business records containing these data therefore is not a search.
The Supreme Court’s decision in Smith confirms the point. At the outset, the Court observed that Smith could not claim that “his ‘property’ was invaded” by the State’s actions, which meant he could not claim any property-based protection under the Fourth Amendment. And as to privacy, the Court hewed precisely to the content-focused distinction that we make here. 442 U.S. at 741. The Court emphasized (literally) that the State’s pen register did “not acquire the contents of communications.” Id. (emphasis in original). Instead, the Court observed, the phone numbers acquired by the State had been dialed “as a means of establishing communication.” Id. Moreover, the Court pointedly refused to adopt anything like a “least-sophisticated phone user” (to paraphrase the Fair Debt Collection Practices Act) standard in determining whether phone users know that they convey that information to the phone company: “All telephone users realize that they must ‘convey’ phone numbers to the telephone company, since it is through telephone company switching equipment that their calls are completed.” Id. at 742. The Court likewise charged “telephone users” with knowledge that “the phone company has facilities for recording” numerical information and that “the phone company does in fact record this information for a variety of legitimate business purposes.” Id. at 743. Thus, the Court held, Smith “voluntarily conveyed numerical information to the telephone company and ‘exposed’ that information to its equipment in the ordinary course of business.” 442 U.S. at 744. Hence the numerical information was not protected under the Fourth Amendment.
The same things are true as to the locational information here. The defendants of course lack any property interest in cell-site records created and maintained by their wireless carriers. More to the point, when the government obtained those records, it did “not acquire the contents of communications.” Id. at 741. Instead, the defendants’ cellphones signaled the nearest cell towers—thereby giving rise to the data obtained by the government here—solely “as a means of establishing communication.” Id. Moreover, any cellphone user who has seen her phone’s signal strength fluctuate must know that, when she places or receives a call, her phone “exposes” its location to the nearest cell tower and thus to the company that operates the tower. Accord United States v. Davis, 785 F.3d 498, 511 (11th Cir. 2015) (en banc); In re Application for Historical Cell Site Data, 724 F.3d 600, 614 (5th Cir. 2013). And any cellphone user who has paid “roaming” (i.e., out-of-network) charges—or even cellphone — should know that wireless carriers have “facilities for recording” locational information and that “the phone company does in fact record this information for a variety of legitimate business purposes.” Id. at 743. Thus, for the same reasons that Smith had no expectation of privacy in the numerical information at issue there, the defendants have no such expectation in the locational information here. On this point, Smith is binding precedent.
EFF: Sixth Circuit Disregards Privacy in New Cell Site Location Information Decision
WaPo: 6th Circuit: No Fourth Amendment rights in cell-site records by Orin Kerr:
Several federal circuits have ruled on whether the Fourth Amendment protects historical cell-site records. Historical cell-site records are the phone company’s records of what cell tower a phone was connected to in the past. The government often uses those records to roughly locate a person’s phone at that time to show the person’s likely location. A federal statute called the Stored Communications Act (SCA) allows the government to access those records with a court order but does not require a search warrant.
