Perhaps the shipping companies hit US first because that's more efficient to them, then they follow on to lesser used ports or perhaps its a case of keeping my biggest customers happiest first and they may happen to be in the US or maybe Canadian retailers ordered later that some of the really big US retailers.
I have no real idea but just speculating a few logical reasons other than blatant discrimination against one country or other.
While we are on the Subject of deliveries, @George, can you please send some cases to NZ. Pretty please ;-)
Source:
http://www.overclock.net/t/1297712/mc-corsair-corsair-900d-godzilla-unveiled/4990