Carpenter doesn’t apply under Davis good faith exception where circuit law didn’t require a warrant before. Besides, here it was harmless at best. United States v. Chavez, 2018 U.S. App. LEXIS 18022 (4th Cir. July 2, 2018):
In United States v. Graham, we held that “the government does not violate the Fourth Amendment when it obtains historical [cell site location information] from a service provider without a warrant.” 824 F.3d 421, 425 (4th Cir. 2016) (en banc). In Carpenter v. United States, however, the Supreme Court made clear that the government’s acquisition of Carpenter’s cell site records “was a search within the meaning of the Fourth Amendment.” No. 16-402, 585 U.S. ___, 2018 U.S. LEXIS 3844 at *30 (June 22, 2018). While Carpenter is obviously controlling going forward, it can have no effect on Chavez’s case. The exclusionary rule’s “sole purpose … is to deter future Fourth Amendment violations.” Davis v. United States, 564 U.S. 229, 236-37, 131 S. Ct. 2419, 180 L. Ed. 2d 285 (2011). Thus, when investigators “act with an objectively ‘reasonable good-faith belief’ that their conduct is lawful,” the exclusionary rule will not apply. Id. at 238 (quoting United States v. Leon, 468 U.S. 897, 909, 104 S. Ct. 3405, 82 L. Ed. 2d 677 (1984)). Objectively reasonable good faith includes “searches conducted in reasonable reliance on subsequently invalidated statutes.” Id. at 239. Chavez does not, and cannot, deny that investigators in this case reasonably relied on court orders and the Stored Communications Act in obtaining the cell site records. Without question, then, the good-faith exception to the exclusionary rule applies to investigators’ actions here.