I bet you that the guy in the article you quoted was, actually, a bicyclist.
I still find it hard to believe that a pedestrian wouldn't hear a moped coming, and move.
I've run into a pedestrian on my mountain bike--I was riding way too fast, on the sidewalk. An old guy came out of the adult bookstore, really fast, probably because he didn't want to be seen.
I smashed right into him, and he fell, half in and half out of the doorway of the dirty bookstore.... I rode off before he could get up.
I can totally see how a silent 10 speed could 'sneak' up on a pedestrian. Still-- I doubt that it would happen with a moped.