Yeah, the statute is clear when a motor vehicle is involved. However, not as much when you aren't in a car. That portion simply says if the licensee is stopped for a law enforcement purpose. That begs the question what if a companion of yours is stopped by an officer while walking down the street for a law enforcement purpose. It may not be clear if you personally are stopped or just your friend. Or if your friend is being stopped but maybe for the security of the scene or another lawful reason, you aren't free to leave even if you weren't the one initially stopped by the officer. There would at least be arguments to be made. However, my advice is to just notify the officer anyways. Why risk committing a criminal offense?