From my experience with bicycles out here - those folks who dress in dark, asphalt colored pant and jersey, on an asphalt colored bike with an asphalt colored helmet can really blend in and disappear from view during a quick glance. I have yet to miss seeing (edit - add seeing) a bicycle when they wear hi viz. Hunters wear camo to blend in to the woods... A biker (bicycle or motorcycle) that wants to wear what amounts to asphalt camo is kind of asking for it IMHO. That said, I agree that hi viz is not the prevent-all when it comes to getting run over. There is no substitute for other drivers being attentive.
Faint is the heart that runs from a fight, but it's a sorry set of legs 'let a man take a beating.