We don't have real free movement of goods between Canada and the USA because the process (at least 15 minutes, probably more plus crossing the border which involved a 1.5 hour wait today) to pay GST and PST and duty takes too long when a consumer imports something into Canada from the USA. Why not streamline it? It's almost as if we don't want to have real free trade!
BTW the above form is the one that was used when I paid my GST and PST for the Bug from Bug Labs which was shipped to Blaine, Washington and imported by me into Canada today. More on the Bug later