I have been involved in two bike accidents, both low speed (30 to 35 mph), one with an open face helmet with shield, and one with a smaller "lid".
The first, I broke ribs, shoulder, collar bone and punctured a lung, with no damage to my head or face except a bit of road rash on my nose (which could stand a little work anyway).
The second with the "lid", I lost a pair of glasses, an eyebrow, good part of my forehead and fractured the C2 vertabrae. I was less than a milimeter from death or paralized.
Lesson learned: I don't ride anywhere without a good, full helmet. I may not look so tough and carefree, but I'm a lot more sure of returning home still sitting upright.
Of course I still believe in freedom to choose, I just pray for those who ride with or without.