Since this thread got political .... The govt is not some abstract, mysterious entity that restricts individual liberty but an instrument of the public collective. When the govt legislates against helmetless riding, its the voice of the citizentry acting through their democratic process. And sometimes, the voting public gets it wrong. Helmetless riding is probably a decision best left to the rider. But there is no liberty or right to helmetless riding. You'd be much better off refutting the safety claims of helmets. The libertariam position is a trendy one but the tradeoff of securing the privileges and benefits of living in a society is the surrender of certain "freedoms." Having said all that, happy trails!
To be clear (and I don't even know if you were addresing my post) I never made a judgment one way or the other on the true function of government -- only the perception of law as restriction on personal liberties, which, in a fundamental sense, it is. But, as you say, for a reason. It's kind of a paradox that libertarianism would ever be described as "trendy" -- it's a uniquely personal vision of what it means to be free, isn't it? I wouldn't say that society doesn't need laws to guide behavior. I would say that
I as an individual don't need them to guide
my behavior. But you wouldn't know that, so you prefer that society protect you from the possibility that I am lying (just like those laws protect me from you.) And because of that framework, we can all just carry on and go about our happy trails without worrying that we missed the memo that all bets were off and that it's time to start eating the weak. But ultimately, I personally really don't care if there is a law about helmets because I'm going to wear one regardless because, when I think about it, I can't come up with a suitable risk-ratio that favors not wearing them. I don't want to crack my head open (not even once) and I don't want my family and friends to have to go through theh discomfort of having to wear suits and things just to watch some dude throw dirt on me and I sure as hell don't want to cost my fellow riders access to a great trail because I smeared my brain jelly on a rock. If soeone else feels differently and can come up with a suitable model that says "go helmetless", I may doubt the mathematics of their probability models, but that's their call.