Check the link, interesting story as well. http://www.cyclingnews.com/photos/2006/giro06/index.php?id=/photos/2006/giro06/vespa/IMG_0677
I think I see why it didn't catch on - top speed of 66kmh? You could only skedaddle at about 42 mph from whatever it was that you just tried to shoot at--and missed because they dropped in their boots laughing at it.