As a UK resident, I asked this question once to a person on the AC Elite reservations line. She said the reason for the limitation of Canadian residence is a tax one on the purchase of this type of service. So if I wanted to purchase one, just use a valid address (such as my parents or a sibling).

It seems like this has nothing to do with who actually uses the pass, just about how the money is collected and taxed.

I have not tried it, but that was from AC itself.