Sometimes on products I buy you see things like "don't put the plastic bag over your head" or "don't leave unattended around children". I always ask myself who that's for and then I remember the USA exist. :)
Edit: Also, we have a proverb here about this exact kind of warning. It goes something like this: "This is an American-grade warning, like not to put your dog into the microwave."
Yes, but not on our territory. ;)