Fake stuff at Amazon is an issue for lots of products.
A real eye opener from Reverb <- more at the link
An RIAA study of the phenomenon conducted this summer found that 25% of CDs fulfilled by Amazon were illegal copies, as reported by DJ Mag and other outlets. In October, Tommy Boy Records grabbed headlines by saying they saw vinyl records for sale on Amazon that the label had never pressed to wax.
Through conversations with record labels and industry watchdogs, it's safe to say that the practice is widespread. In fact, calling counterfeiting widespread would be like dubbing Genghis Khan disagreeable.