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.
Death is like an old whore in a bar, I'll buy her a drink but I won't go upstairs with her. Hemingway