Just how I feel. It's all about choice and what the rider feels safer wearing.
This is from a (U.S.) Government study on motorcycle helmet effectiveness in crashes above 13mph. I personally would rather have no nose or jaw than live without the use of my arms and legs, but thats just my personal opinion. Can you tell I'm a member of A.B.A.T.E.(Fl.)???
7. As a result of (5) and (6), we establish that a tradeoff between head and neck injuries confronts a potential helmet user. Past a critical impact speed to the helmet (13 mph), which is likely to occur in real life accident situations helmet use reduces the severity of head injuries at the expense of increasing the severity of neck injuries.
Sorry for the hijack. But I believe that a rider should wear or not wear what he/she wants to. I have two friends that are in wheelchairs from bike accidents and one was wearing a helmet and one wasn't. Neither of them had head trauma, but both broke their necks. I think that a full face helmet can save your life, just as easy as no helmet can. It all depends on that specific incident and how the rider falls and what or what he doesn't slide into/under.
Be safe and aware of your surroundings at all times, and NEVER let your motorcycle drink...