I am skeptical that a 20 pound scooter can be fall-proof with a wriggling 200 pound person aboard. If the person is riding it like a bicycle that's one thing. If the person is simply expecting the scooter to stay upright No Matter What (perhaps leaning over the side to take pictures, etc.) then some considerable counterweight would be needed.
The comment in the article that getting hit by the scooter would be like getting hit by a pedestrian, sounds silly. Suppose it is only 20 lb. Imagine getting hit by a pedestrian on skates. Even moving at walking speeds, that is going to be a significant impact.