Or, more likely, a total boycott of that coded product. In this case, it means do not buy at any price. But at the point of purchase no one can see that this product is always generating red lights everywhere, and for everyone.
A yellow light is a less strict and more common way to signal a problem with purchasing a given product, or a price at which one should buy it (but not for a higher price). A green light just means "buy", and like the red can be "at any price". KitKat McFlurry for instance is red only.