Expanded from my earlier post...
With some cursory looking around I come up with the fact that France, Germany, Italy, Spain, Poland, Netherlands, Greece, Ireland, Norway, and the UK all get a 2-year warranty, and there are likely many others (for some reason, Switzerland gets three). So, the US warranty seems in line with that.
As far as the Canadian warranty goes (4-years), it may be the result of supplimental coverage provided by M-B Canada or smart Canada. Good for them.
If there is a bone to pick, it may have to be picked with smart GmbH and not PAG. Could it be that PAG's "under discussion" stance is to consider following Canada??