No. What happens is that publishers can distribute books that have their origins in the U.S. or the U.K. and extract 10% or 15% more. An individual can go around both the bookseller and the publisher and buy without that tariff, but it does not provide an advantage for an American book over a Canadian book; it just explains 10% to 15% of the differential in price.
On December 11th, 2007. See this statement in context.