Maybe it’s not a fair comparison, but I think it’s been shown that tobacco warnings are effective even though they’re so common to be “fatigued”.

I do believe this is an unfair comparison. With tobacco the warnings are always true, but with prop 65 the product might not contain any cancer causing ingredients, but the warning is there just in case.

It's much easier to tell yourself prop 65 doesn't have to be avoided because "it's probably just there to cover their asses" wile tobacco products have real warnings that definitely mean danger (though there are people who convince themselves otherwise_