I agree. The larger point I think you're making is that there's always going to be leakage in the system. I'm saying there could be more comprehensive multilateral cooperation, but there's always going to be leakage.
In similar problems that are occurring, we're cracking down on tax havens, and some of them are cooperating and some of them aren't. The OECD has reviewed certain countries and it said they're not meaningfully implementing the TIEAs. As long as you have one country that's not playing ball—and this is your point, I think—then you're going to have leakage out of our system.
Maybe there are ways to reduce the problem, but I don't think it will ever go away.