Apparantly Amazon USA have (word auto-deleted)ed up big time and shipped the Blu Ray containing the last episode... my friend messaged me to say he's already watched it... well done BBC
Oh, I've no doubt that they're rather miffed by it, I'm just a bit bemused by the original rather sarky "well done BBC" comment.
It's a mistake. They happen. But I can't see why it should be such a big deal as far as fandom is concerned. Okay, a few people already know how the season concludes, but you're only going to be spoiled if you choose to go and specifically look for that information sometime over the coming week.