https://disneyworld.disney.go.com/en_CA/ has been changed ... they dropped the last part "en_CA".
So in my case, I go to http://disneyworld.disney.go.com/ and then click Tickets -> Special Offers and it brings up the special offers page. I know this is the Canadian page when I click the play stay and Dine package, since it shows the Canadian offer deadline "Book by February 18, 2013!".
I can also see in the path of the website site "stayplaydineCA&market" which denotes to me that they have flagged my IP as Canadian.
So, several things could be happening here (and I have seen this with Disney in the past). They create a new content specifically for certain Markets. In our case SPD will undoubtedly stay up until mid Feb for canadian IP's. We in Canada may not see their US based offer until they release it to our IP's, or there is someone here who masks their IP, or someone from the US posts this for us to see.
Ted