[sherincall]

Even riding a motorcycle without a helmet has externalities - more severe injuries from accidents could raise insurance rates across the board, and these people take from the ER/ICU capacity that others could use.

I guess you could have a policy of just letting them die if they get into an accident without a helmet, but that its own host of problems.

[fred_is_fred]

In fact not wearing a helmet might be cheaper - a quick death versus a lifetime of care.