Here's some ways of looking at it that are not loyal to the government mind control system:
1. It's still legal I think to leave the country.
2. It's still legal I think to take one's property out of the country.
3. In the end, it's the Canadian's responsibility to obey the laws of his nation.
4. "Exporting" is word defined under commercial law and has nothing to do with what we're talking about here.
5. Governments have become experts at convincing uneducated humans that those humans are "required" to do things they actually are NOT required to do. They know those humans will never ever actually read the law, let alone in context.
Keeping the above in mind, if one decides to act as a Citizen and sell his property to someone in Canada, they need to remember that the U.S. government considers you a "person" and/or "individual" until proven otherwise. Under the law, those terms DO NOT mean the same as American Citizen.
If you're going to act as a Citizen, who has rights, you don't ask permission, and you certainly do not use the aparatus that is designed to track "persons" and "individuals" via applications to exercise a person's "privileges."
Now, since governments have made being a Citizen, and exercising Citizen's rights impossible or not worth the effort, I would tell Mr. Canadian to move his behind down here if he wants to buy my gun.