I agree wearing a helmet is the smart and correct thing, but, I also believe in freedom of choice. I like the way the Florida law is stated, IF and ONLY IF you have ample insurance, you may ride helmetless.
I have only rode lidless once, through the Tomoka Forest in Florida. A low speed ride, but it still made me nervous.
Tiered licensing? Hmm, I still believe in freedom of choice, but, something should stop an untrained 16 year old from buying and riding a 186 MPH superbike.