I just bought a Canada flag (drapeau du Canada) from a shop in Cowichan. I had looked in a bunch of places (Wallmart, Canadian Tire). Lots to choose from, but I only found one shop that had the right size courtesy flag for my boat (9"x18") and was Canadian made. The many others were Chinese made with 2x3 dimensions (and half the price).
My flag is from flyingcoloursintl.com, a Canadian company. Their website has lots of info but they also sell Canada flags in the wrong dimensions (4'x6', etc.). They even sell "Government Specification Fabric" flags in the wrong dimensions. Who knew? I never noticed until this thread. My new flag is definitely different than my past flags.
I think that if my U.S. flag was the wrong dimensions, say perfectly square, both I and the manufacturer would get lots of comments, none good. Canadians are too polite?