This is a crime and they should be imprisoned for life. Just a guess but I'm assuming you are ok with this type of crime but not thugs mugging ppl or getting caught with some weed.
They are going to do this regardless of what taxes are. It needs to be punished accordingly.
Punish them for what? Have they broken any laws?
Tax evasion, likely. But hey let's just start the investigation based on public discontent. Then after awhile get the emails and if nothing related to tax evasion sticks, I'm sure we'll find some other punishable transgression.
So use the tax system as punishment for success? How enlightened.
Chances are pretty good that there have been no laws broken, and so nothing to prosecute them with. Unless it is illegal to put your money in a bank in another country, there is nothing to be done.
They always have the option to permanently relocate somewhere more tax friendly. Some island in the middle of nowhere. But then...they may not be able to benefit as well from their original first world economy. Which is the catch 22 of the tax is theft argument.
They want all the benefits of a humming economy, trained and secure labor pool, favorable market conditions and infrastructure, affordable and well defended land, things that come a great public and private cost, generations of effort. But they don't want to pay for it. The greatest winners in society don't want to pay for the conditions that were necessarily required to win so hard.