Dealextreme sells at least a few counterfeit knives. I bought what appeared to be from the site, a generic Cold Steel knockoff out of curiosity from them. What I got was an out and out counterfeit, marked as if it were authentic. Even the box looked legit.
To their credit, they don't claim these to be authentic. However, there is nothing to stop someone from ordering these in bulk and peddling them on ebay as authentic. This has happened with the Cold Steel knockoff already.
Bogus products on ebay can be outed, and the merchandise banned. But still, this is a serious problem for manufacturers.