AMERICA has become the country of the warning label. California is the warning-label state. Since California voters in 1986 approved Proposition 65 -- which mandates warnings when people are exposed to known carcinogens or chemicals that cause birth defects -- to live in California is to be warned. Most office buildings and parking garages post Prop. 65 warnings. When you fill your gas tank, there's a warning. When you go to a department store or a restaurant, there are warnings. Ditto the grocery store, where there are warnings not just about lighter fluid, nail polish and the effects of alcohol,...