I would like to point out that there are many ways to fake out chemical tests.
Chinese milk producers famously sold fake milk, so the government mandated a chemical test for a particular protein found in milk. Chemists discovered that melamine would fake out the test, i.e. cause the fake milk to "test positive" as being real milk. Hundreds of babies and children died from ingesting the tainted milk.
I would like to point out that there are many ways to fake out chemical tests.
Chinese milk producers famously sold fake milk, so the government mandated a chemical test for a particular protein found in milk. Chemists discovered that melamine would fake out the test, i.e. cause the fake milk to "test positive" as being real milk. Hundreds of babies and children died from ingesting the tainted milk.
Aha, this proves that milk is just a hoax!
No, it means the test was useless.
Touche.
(But think about it, the test actually stopped a lot of fake milk from making it to market before some companies started adding melamine.)