The Fifth Circuit has held, in United States v. Guerrero, that the Supreme Court’s ruling against warrantless searches of arrestees' cell phones in Riley v. California doesn’t extend to historical cell-site location data held by cell-phone service providers.  The court determined that a defendant did not have a reasonable expectation of privacy in the data about the location of his cell phone because that data had been disclosed to a third party, the cell service provider.  However, the court acknowledged that in future cases interpreting Riley, courts may reconsider the third-party doctrine and ultimately hold that people may retain a reasonable expectation of privacy in information disclosed to a third party.