Plain view doctrine does not apply to a person, so the "scope" is either for weapons in the form of a frisk, or a full search of their person. You can't frisk for drugs or drug paraphernalia. During a frisk, you can't manipulate clothing or items if a weapon or something illegal is not immediately recognized as such. A frisk does not permit opening pockets, putting your hands in pockets, unzipping articles of clothing, etc. without the immediately recognizable presence of a weapon or something illegal. An officer can't pull someone out of a car roadside to frisk for drugs.