No doubt about it, it is a delicate subject. One of the moderators here did have a fairly long duration thread on FGRV that stayed on track with only a some firm guidance a couple of times.
One factual comment to correct part of your statement that you "can't take anything into Canada". You can and if you do some homework you can find out the exact situation. Actually the Canadian situation is easier because the rules apply nationally, there's only one set of rules to research as opposed to 50 sets of rules in the US.