There are a lot of compliance warning labels that don't really mean anything. When I first visited California, I was pretty alarmed by the Prop 65 warnings plastered all over everything. Now I can't even see them anymore.
Propositions and people covering their asses is different than ignoring instructions for using a medical device. When it says "ONLY USE DISTILLED WATER", then that should give a reasonable person pause. It doesn't mean use any old water, it means use distilled water only.