Things get rough and they renounce citizenship? Good riddance to them.
The US has a financial Berlin wall: anyone trying to get away from the taxation power of the US Government has to renounce citizenship, and even that costs roughly 50% seizure of assets.
These guys are probably getting away before it becomes 100%. For them, Atlas has Shrugged. If November doesn’t save the US, then I expect the trickle will become a flood.