Many of these designers have factories in China simply because it is more viable where labour is cheaper. In the process of making the garment, some of the pieces do not pass the QC due to slight irregularity. These "defective" pieces get into the hands of people who are willing to take them in at a fraction of what the "perfect" pieces would normally cost and sell them as "overruns". Personally, I wouldnt classify them as fake. To me people who sell fake are those that "borrow" the original and replicate the design using similar materials and then put on the name bearing the label.