In response to a report of an argument on a public sidewalk, a police officer approaches two people standing in the vicinity of the reported dispute. The officer requests that each person provide her name so the officer can run the names through databases to which the police department subscribes. After searching each name through various databases, the officer might discover that one of the individuals made several purchases of cold medicine containing pseudoephedrine and that the other just received a license from the State to procure certain hazardous chemicals. These two people might be in the early stages of setting up a methamphetamine ring, or they might respectively be a person getting over a cold and an entrepreneur. In either case, merely by giving her name, each person provided the police officer with information that she could have reasonably believed might lead the officer to incriminating evidence.
The potential for a name to be self-incriminating presents a question about the applicability of the Fifth Amendment’s Self-Incrimination Clause. In California v. Byers, the Supreme Court held that a person cannot refuse to state her name in the course of a traffic stop based on the Self-Incrimination Clause. The reason is because the statutes applicable to traffic stops are primarily regulatory—not criminal—and the Self-Incrimination Clause is inapplicable to noncriminal regulatory inquiries. Outside of the context of a traffic stop, the Supreme Court has held that the Fourth Amendment prohibits a police officer from stopping an individual to ask for her name unless the police officer has “a reasonable suspicion, based on objective facts, that the individual is involved in criminal activity.” If a police officer approaches an individual without reasonable suspicion or probable cause, “the individual has a right to ignore the police [officer] and go about his business.”