Found this reddit post from a few months ago. Bioshock Infinite purchase worked for someone in Australia.
http://www.reddit.com/r/GameDeals/comments/1oqlkn/amazon_digital_bioshock_infinite_pc_999/ccusrtd
I have an acquaintance who tried to buy something on Steam from the Ukraine store - the game was considerably cheaper, like about 1/10 the price in Australia.
The purchase went through, he downloaded it, but when he tried to run it, it was region locked and would not start on his otherwise Australian Windows/Steam/everything else.
He argued and eventually got a refund.
Really I CBF at the moment, lack of time and money doesn't help, and lack of a useable games rig is another contributing negative factor.
Maybe this kind of special offer should say "US only" in the title?