In Florida v. Royer, the U.S. Supreme Court ruled on a case involving Fourth Amendment rights against unreasonable searches and seizures. The defendant, Royer, was stopped by law enforcement at an airport under suspicion of drug trafficking due to his behavior and appearance matching a "drug courier profile." Officers took him into a private room without obtaining consent or informing him he could refuse their requests for search. They found illegal drugs in his luggage after he voluntarily revealed them but before being informed of his right to decline the search request. The court held that while initial engagement with Royer did not violate any constitutional rights as it fell within permissible police-citizen encounters, moving him into the private room escalated this encounter into an unlawful seizure because there was no probable cause nor warrant obtained beforehand. Furthermore, although officers argued that Royer's cooperation implied consent to the search which would make it lawful despite lack of formal advisement about refusal rights; however,the court disagreed stating such consent must be freely given and cannot be presumed from potentially coercive situations like these where individuals might feel compelled to comply with authority figures' demands out of fear rather than genuine willingness.

In the dissenting opinion for Florida v. Royer, Justice White argued that the majority's decision was inconsistent with previous rulings on Fourth Amendment rights and would unnecessarily complicate law enforcement procedures. He contended that there was reasonable suspicion to detain Royer based on his behavior and appearance, which matched a drug courier profile. Furthermore, he believed that moving Royer to a private room did not constitute an arrest but rather a justifiable escalation of investigative detention given the circumstances. The police had acted reasonably in their efforts to confirm or dispel their suspicions without infringing upon Royer's constitutional rights until they found evidence of wrongdoing during this lawful detention period.