My friend bought a Koetsu Urushi from one of the gray market resellers and he never had a problem.
(Of course, had he had a problem......)
From what I can tell, people just buy them from dealers in Asia, particularly Japan and Hong Kong, at discounted prices, as they buy in bulk, and so get them for almost the dealers cost, which is about 1/3 the regular price. They then resell them for about half the regular price and make a small, but decent profit.
As far as fakes, I suppose it is possible, but I have not heard of any problems. (You should check on Audio Asylum's Shady Lane to see if you can find any problem dealers.)
I do know that Juki2, on Ebay is considered to be very reputable, and he sells Koetsus, or used to at least.
Good Luck!