I'm not so sure about that S.J. I think if you show up at a hospital in the U.S. without funds or health insurance- they will just refuse to treat you. So I don't think there's a problem for any but the victim if he's not covered.
In USA it is required by law that a hospital cannot turn anybody away for emergency medical help. They must treat the patient. Sure they can (and will) send him the bill if he has no insurance, but if he cannot pay, that is the end of it.
And that is the problem with young people not having any insurance. A young man thinks he is invincible, that nothing will happen to him and he does not take out medical insurance.
But if he gets involved in car accident or is diagnosed with cancer, hospital must give him emergency treatment. Since the young man cannot pay, hospital is stuck with the bill. So young people not having insurance is as much of a problem as the poor not having insurance.