The parents do. And with Hawaii's distended cost of living, very few parents will be able to afford to pay hefty fees for their children's nicotine addiction. The idea of charging fines to minors for tobacco consumption is a transparent attempt to milk even more money out of tobacco abuse. Taxes on tobacco increase government revenue, and tobacco industry court settlements have been a source of funding for the proposed fluoridation of water. Kids are one demographic, however, that we shouldn't be exploiting for revenue, particularly in our financial state.
Smoking is a self-destructive behavior.
Yes, it causes lung cancer, heart disease, complications during pregnancy, emphysema, etc., but thanks to new laws limiting smoking to certain areas, it's largely self-contained. Criminal penalties are used to keep people in line in their treatment of each other. Speeders are ticketed because they're a danger to others. Drug addicts are arrested because their substances are illegal and tend to propagate through them. Stores that sell to minors are fined because they are exploiting minors.