Do you mind sharing where you are getting the keys from?
I might be interested, just nervous that the keys could be from some... illegitimate source. Just because they activate today, doesn't mean they can't be banned tomorrow, etc.
Sure, I personally purchased two copies, one I kept the other I planned on selling for bitcoins. I returned the original one I had bought for myself after getting buyers remorse, I said I had used the CD key and they said they could not give me a refund due to it being open but could instead exchange my copy. So here I am with two copies of Diablo III and the one I activated is the only one that would be at risk of being banned, even though they knowingly accepted the return even though I said I had used the CD key.
My close friend did the same thing only he planned for the second copy to go to his older brother for his birthday, his brother sold his desktop and now only has a laptop that would barely be able to play it, so I am going to give him cash equivalent for the bitcoins I receive.
EDIT: Once these are gone I will be willing to purchase more copies and sell them for 55$ if there remains a demand for it. There is a little mom and pop game store in my city that do deals if you buy 3 games+ you get ~30 dollars off.