I have a quick response to that with two quick points.
The first is that on the question of mobility of high earners, there is certainly some evidence that there is some sensitivity of high earners to tax rates, but I think we don't want to overestimate that, especially when we're looking at moving between Canada and the U.S. People are going to be less likely to move there than they are among countries in Europe, for example, for many different reasons, especially when you're looking at the soccer player study.
It is important to consider, but I think it's also important to remember that it's not just tax rates that matter. There are other factors, such as quality of life, and other aspects of society that people choose when they choose where to live.