Can governments purchase user records as an end-run around the warrant requirement imposed by Carpenter v. United States? As a matter of Fourth Amendment law, the answer is “yes.” Companies have common authority over their business records. Common authority allows companies to consent to a government search of their databases even when their users oppose it. A voluntary sale manifests consent, permitting the government to buy access to Carpenter-protected records without a warrant or cause. Arguments exist for why a different rule may be justified someday. But for now, and for the foreseeable future, Fourth Amendment law permits buying business records even if users have rights in those records.
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