If it’s enough money the IRS will and can go after them very easily. Most countries to work with the US. That’s why we give so much foreign aid. Even Switzerland has changed their banking laws to allow the IRS access to their accounts.
Big Brother can and will get you if they want to. It’s a big risk for them.
It’s better to just kill the these stupid tax the rich/wealthy only. Atlas Shrugged is more true today than ever.
Not as easy as you think. Current least of over 90 countries not on FATCA and Morocco does not report and will not.
https://best-citizenships.com/2019/12/06/non-fatca-countries/