It's also problematic in other way, my friends moved to US for a job for few years and had kids there. US gives you citizenship by place of birth so the kids have US citizenship. Now that they are back they are in a bit of a pickle not knowing what to do, the kids might be screwed and own money to the US for nothing when they grow up but renouncing it now for them also doesn't make sense (if even possible) because they might want to have it, who knows.