I know someone that owns multiple properties, and says that each one is his "primary residence" for when he sells and or gets mortgages on them. He used to say that Banks had no way to find this out.
So for those [local Canadian] sellers who are investors with multiple properties - and there are many of these in Calgary, this now suddenly closes the loophole, where Joe with 4 homes will now have to pay capital gains taxes on the other three when he sells because it's now recorded on his return.