Well...dogs can smell crystal meth, which is a phenethylamine, so they are no doubt capable of it, but there are so many RC's with different scents that it would be impossible to train the dog to hit on any and every pack. Trained drug dogs cost in the neighborhood of 50K, and they train them for the high-dollar seizures of crystal, heroin, weed and cocaine. These counties aren't after little bags of alphabet soup. They are after the big busts of cash, drugs, guns and cars, of which they get a cut.
:D