Aepervius
Non credunt, semper verificare
If you are a homeopathic preparation house, you can fill up every bottle of every desired end product with the same plain water. Since there is no known way of verifying what's in a homeopathic "medicine," there's no way of proving that you did that.
Profit with no risk of detection.
They don't do it. The money they would spare would be ridiculously small, and the advnatage NIL in comparison to the risk incurred (legally that would be a fraud ; and their business would be shot if it became to be known).