Looking for Reality
Forgive me, but I can't tell if you're being serious, or just cynical/sarcastic (I presume the latter?).
I have a number of clients in CA...every one of them has a warning posted in the front window and on every entrance door.
I asked two of them "Why? I know what you make here."
The answer was pretty much what I wrote...they didn't make the sheetrock in the walls, or the paint, or the carpet...and surely there's something in there made in China under questionable controls...and the warning signs only cost ~$50USD to cover everything.
One of them outsources janitorial, and it would cost more than $50 to check their chemicals every time they come in to clean...
It is a very easy cost/benefit equation which makes Prop65 essentially useless in a litigious society. Especially given supadrai's description of (my paraphrase) "guilty until proven innocent".
Warning labels cost 1.6 cents at Uline...with the marketing "Apply to items that may contain Prop 65 chemicals "...note the "may".