Definitely! Especially if they use a little maple leaf as a "dot" in the domain name, like maps[maple]ca :) Canadians are quite submissive to this type of advertising. Remember the "i am canadian" ads?
I personally use .ca domains all the time for Canadian sites. If there is any hint of "internationality" of the business/service, then I get a .com. If it's a local mon'n'pop store, then def a .ca