I have the same problem with Canadian immigration policy as I have with US immigration policy...it is too lax. The 911 terrorists may have "done business" within the US, but they got here via Canada...and that says something terrible about both our countries.
As for my friend, he was fined by the Canadian government (I assume) while trying to pass through customs at the airport after landing (not really an option to turn around...he was already there). The crime was committed in New Jersey in the late 1970's. And if his nationality had been Syrian I'm sure they would have sent him here for us to deal with, anyway.