There is a huge problem right now with Chinese knockoff of name brand equipment. If you look at the listings on Ebay, you will find a lot of clubs listed as TaylorMade or Callaway or Titleist at unbelievably low prices. While it could be somebody dumping his excess, its also likely that they are imitations made from low-quality alloys.
The ironic thing is that a majority of real clubs also are made in China.