Washington (CNN) The Supreme Court Monday said that just because the name of a driver of a rental car is not on the rental agreement, that does not automatically mean that he or she has diminished privacy rights.

The unanimous opinion sends the case back down to the lower courts. The ruling is a victory for privacy rights advocates who were concerned that police could find reasons to stop rental car drivers for minor infractions knowing that they could engage in searches without the driver's consent.

The case dates back to 2014, when Terrence Byrd was stopped by police for a minor traffic infraction. Police noticed that he appeared nervous, and when they asked him for the rental agreement for the car, his name was not listed as a permissive driver.

The officers said they did not need to consent to a search of his car, because his name was not listed on the rental agreement and as an unauthorized driver he had no reasonable expectation of privacy. They found 49 bricks of heroin in his trunk and body armor.

Byrd's lawyer sought to suppress the evidence against him, citing the Fourth Amendment's guarantee against unreasonable search and seizure. He noted that Byrd had the permission of his girlfriend, whose name was on the agreement, to rent the car.

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