We have been struggling with this problem for quite a few years. About 5 years ago we bought 2,500 high-end $5 transistors (1-reel) for an industrial engine control we've been building for over 10 years. We buy them quarterly and from the same reputable vendor; not a broker. Parts were in the proper bag, proper tag, and proper markings on the body. Only problem was they were cheap low-end counterfeit transistors. Fortunately, our automated test stand was rigorous enough to detect the problem; this time. It is extremely difficult for the mega-firms (Boeing, Raytheon) to have counterfeit detection programs and they can afford the expensive toys like electron-microscopes. For us small manufactures we bear the liability without any feasible means of controlling the problem. We only purchase parts from reputable wholesale suppliers (Arrow, Future, Avnet, etc) who theoretically buy them directly from the manufacturer but that is clearly not good enough as our previous problem illustrated. When the manufacturer is in China, Indonesia, Vietnam or some other 3rd world location it is too easy for the criminals to break into the supply chain.