The big problem I see with these knock-off cables is this... many times either the vendor or the consumer has no knowledge of the fact that they are fake! ( much worse if the vendor does actually know, and tries to pass them off as real!)
This situation leads to a cable that is really worth minimal $$ selling for an amount that is possibly comparable price wise to the real thing and leading to ongoing fraud, whether intentional, or not. Furutech cables/products come to mind here, as they have been copied extensively and sold all over with little knowledge of what is the legitimate product..and what is a cheap knock-off!!