I think this is a bigger problem than a lot of people realize. Part of my job is Aircraft spares assessing were Bogus spares are a big issue.
There are some easy to spot issues. A lot are very difficult if not impossible. They duplicate Certificates of Conformance and packaging and slip these into the supply chain. I often wonder how many spares are not detected. I recently had a case were our supply people had ordered a spare and the quote from a company come back saying they could supply had all of the certifications but i would have a certain amount of lead time. This is not unusual. Some of the wording from this US based company did not seem quite right. Our supply people asked me to have a quick look and see if I thought it was legit.
The first thing I did was have a look at the companies website. It was very professional and had photos of the inside of there factory. It also had addresses and everything you would expect to see from a large manufacturing company. At this point I was thinking it is all looking good but I decided to put the address of the manufacturing plant into google maps. Once I saw the small industrial factory I knew there was an issue. Unless it was some kind of tardis there was no way the photos on the website website were taken inside the factory. I pushed this up the chain and last I heard was that this supplier was not been used.
I have no doubt that there are not millions of fake spares been sold a genuine in the automotive industry as the checks and balances are not the same as the Aviation industry.
Steve