I have some experience of this; I naively bought a cheap Specialized jersey from what looked like an American website thinking it was surplus stock or something. Then I discovered it was coming from China and when it arrived I knew straight away that it was a fake. The colours were wrong and the quality terrible so I stuck it on
Ebay, only to be reprimanded for selling fake goods!
More recently I bought an FSA chainset from Ebay for £170. The seller in Taiwan told me it was genuine but "excess stock" so I placed the order. It arrived wrapped in brown paper and on close examination it looked too well-made to be a copy; it weighs what the spec says it should and has performed well for almost three years as long as you ignore the design limitations of the BB30 system. The amount of work and detailed finishing that has gone into the chainset makes me believe that it simply wouldn't be worthwhile making fakes; it can only be a factory over-run and if these can be sold as cheaply as this was sold, then we are being seriously ripped off when we pay the full £700 list price.
Call me an idiot but I work in manufacturing and I see how much gets rejected, over-produced, dumped and sold off cheap in every industry in which I'm involved.