You have a number of questions in there. I'll try my best to answer all of them.
With respect to the agreement with the United States, after 9/11 there was an agreement signed by Canada and the U.S. that ships coming into our ports have to be subject to radiation detection. That is why CBSA mandates container ships to pass through certain ports of entry. These are called first ports of entry.
I'm not sure what you're referring to with respect to—