In point of fact, Canada doesn't tax on the basis of citizenship. Again, I seem to be picking on the United States, but it's the only country that actually taxes—with a possible footnote for Eritrea—on a citizenship basis. We tax on a residence basis.
It's true that we try in our tax treaties to have a provision to make sure that in the case where two jurisdictions both claim a taxpayer as resident there are rules to resolve that, to figure out in which of the two countries or jurisdictions the person truly is resident. It's not as though there would be tens of thousands of people in those circumstances, however, who would fall out of the tax net as a result of the treaty changes. As we said in our opening remarks and have touched on since, the tax treaty provides certainty in that respect—rules to make sure we can figure out when a person is resident and where they are resident.
In point of fact, the essential point is that for most taxpayers that answer will be clear. What the treaty does is ensure that there are limits on each country's right to tax and that there's an ability to get a credit, or an exemption, but in the case of shared taxation to get a credit for the tax that's paid in the other country to eliminate double taxation.