In the 1996 case Ohio v. Robert D. Robinette, the U.S Supreme Court ruled that police officers are not required to inform motorists of their right to refuse consent when asked if they can search their vehicle during a routine traffic stop. The case arose after an officer pulled over Robinette for speeding and subsequently found illegal drugs in his car following a consensual search. Robinette argued that he was unaware of his right to decline the officer's request for a search, thus making it non-consensual and violating his Fourth Amendment rights against unreasonable searches and seizures. However, the court held in a 9-0 decision that while knowledge of one's ability to refuse is relevant factor in determining whether consent was voluntary or coerced under duress, there is no constitutional requirement mandating law enforcement officials must always inform individuals about this right during such encounters.

In the dissenting opinion for Ohio v. Robert D. Robinette, Justice Ginsburg argued that the majority's decision failed to adequately protect citizens from potential police coercion during traffic stops. She contended that officers should be required to inform drivers when they are free to leave before asking for consent to search their vehicles, as this would help ensure that any subsequent consent is truly voluntary and not a product of intimidation or pressure. Without such a requirement, she warned, law enforcement could exploit the inherent power imbalance in these encounters to obtain "consent" under duress or out of fear of reprisal if one refuses - effectively circumventing Fourth Amendment protections against unreasonable searches and seizures.