An officer working in a department that doesn't provide bulletproof vests might be justified in making more frisks, or a rookie officer might be justified in making more frisks, but generally, a frisk is only permissible when there are articulable facts which indicate the person is armed or dangerous. This prevents them from returning to the vehicle and using the weapons against the officer. For purposes of questioning, an immigration officer can detain people believed to be illegal aliens. The person need not be entering the country. Nervous appearance and ostentatious apparel, among other behaviors, justify stopping a person as a suspected drug smuggler.
Officers have the right, without probable cause, to take fingerprints at a crime scene.
However, probable cause is needed to take fingerprints at the stationhouse. Speed is essential here, as only an immediate and continuous pursuit from the scene of a crime, depending upon the gravity of the situation, will justify triggering exceptions to the warrant rule. Questioning during a stop does not require Miranda warnings, but the questioning must be done at the place where the initial stop took place. Otherwise, Miranda warnings must be given. These are illegal in some states, and involve a dual motive of the officer in traffic stops.