At the Becker-Posner blog, Posner writes:
A law aimed at reducing obesity would be paternalistic if obesity did not produce external costs, but it does, because obese people consume a disproportionate amount of medical resources, and there is extensive public and private subsidization of medical expenses (private through insurance pools that are unable or forbidden to identify and reject high-risk insureds).
Exactly! And for the same reason, I feel that the Indian government is in no position to impose a mandatory helmet rule (and similar personal safety regulations, like it tries to every now and then), because it bears no costs whatsoever in the event of an accident. Along the same line, like Posner reasons, governments that do bear considerable costs in the event of an accident, have a ledge to stand on when they coerce people into safety. It is unfortunate that these governments force the contract upon its citizens in the first place, but that is a different story by itself; which, like Becker notes in his response:
But the alleged “externality” with regard to obesity is due only to the government’s subsidy of medical expenditures, so that it is a case of one government intervention- justified or not- causing another intervention-control of eating.
In not as many words, I said the same thing a couple of years back. Oh well, I feel supremely smug now that two awesome people agree with me. Sadly, it’s going to rub off on some poor soul who meets me next.