I think that the integrity of the physical supply chain for IT vendors is a substantially underestimated risk. This article from the IEEE considers aspect of the cloning process and basically concludes that little can practically be done today.
And unlike counterfeit electronics of the past, modern clones are very sophisticated. Previously, counterfeiters would simply re-mark or repackage old or inferior components and then sell them as if they were new and top of the line; the main problem with these knockoffs was poor reliability. Cloned electronics these days are potentially more nefarious: The counterfeiters make their own components, boards, and systems from scratch and then package them into superficially similar products. The clones may be less reliable than the genuine product, having never undergone rigorous testing. But they may also host unwanted or even malicious software, firmware, or hardware—and the buyer may not know the difference, or even know what to look for.
This is an opportunity for IT vendors to differentiate their products. Vendors has been cracking down on grey market to protect revenue but is there a security case to made here ?
Invasion of the Hardware Snatchers: Cloned Electronics Pollute the Market – IEEE Spectrum : http://spectrum.ieee.org/computing/hardware/invasion-of-the-hardware-snatchers-cloned-electronics-pollute-the-market