I don't think SC had anything to do with it, there is no way that Apple would willingly participate in such a plot. It was a mistake at Apple. A mistake that in most circumstances would have gone unnoticed, but it just happened to occur at the exact time that the sneak peek was due and that a routine server maintenance was taking far longer than it should have which got people thinking that the update was coming.
I checked the App Store before these images were leaked and unsurprisingly saw nothing. But after reading the first post about it here went straight back and there it was exactly as many different people have provided many different screenshots of from different App Stores around the world. A few minutes later it was gone.

