and I don't see how drug dogs trained this way would help detect cocaine in, say, a suitcase, vs a person who had used cocaine but was carrying none with them.

That's how i read it at first, but it could also be that cocaine goes through fermentation during it's extraction, and that if that's done near human settlements, air pollution contaminates the final product, making it detectable.

Cocaine hydrochloride's vapor pressure is negligible, AFAIK. I always thought that the "smell of cocaine" is actually the smell of solvent traces or other impurities left from typical production routes.

I'd love to see a dog detect the odor of an undoped polycrystalline silicon wafer.

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