As long as I don't have to pay for someone's medical care via taxes or higher insurance I'm all for the law of the jungle when it comes to seatbelts.
Me, I wear mine because I prefer to be strapped into the car, I'd put a 4 point harness in if my seats would accomodate it, I don't like sliding around when driving fast.
To quote the great Walter E. Williams, "That is not a problem of liberty, that is a problem of socialism".