if you include the visor area and the small areas to the left and right of the visor it's a whopping 44.4% chance those areas will hit, if your noggin hits the pave. 44.4 is creeping up on a fiddy fiddy shot man.
Those numbers don't escape me, BUT BUT BUT - take a look at an open face (3/4 helmet, I don't wear 1/2 shells) they have a significant area protruding around the forehead and often cheeks which MAY prevent or minimize impact with a road surface. I know just from bumping my helmeted head on things when leaning in for a closer look (say checking something on a bike with the helmet on - or attempting to give my wife a kiss with the helmet on etc).
Granted uneven surfaces, rocks, trees etc can post a hazard, I'm just saying that again, the Hurt numbers don't tell the whole story.
And of the two close friends I know that have had offs, the both hit in those areas. As the last crash I saw (track) dude slid on his visor and chin bar quite well.
Notice you mention a track accident - good chance the speeds and conditions of that accident differ from what I tend to expose myself to on a regular basis. Again, not saying it can't happen, just talking about odds.
I'll keep my full facers.
I'm not trying to talk anyone out of it. I'm just saying don't be too cocksure that others are "wrong" with their choices.