Swiss banks used to be legendary for their secrecy, and anonymity. Then government got 'em by the balls, and threatened to not allow them to conduct business inside the united states, and now they play ball. My Aunt is a dual citizenship American and Swiss, and one year she was assessed a pretty good tax bill because she hadn't been filing tax returns in the states for decades because she didn't live here. After the swiss banks opened up to the US fed, they found her accounts, and established that she owned some back income taxes. Renouncing her US citizenship wouldn't have made the tax bill go away, and she was concerned she wouldn't be allowed to travel to the united states anymore, even as a swiss citizen. To this day, even though she lives in switzerland, she still has to file a tax return each year. Granted you get a deduction for up to $150K for your earnings overseas, and she's retired now, her pension falls under that so she pays no taxes, but she still has to file a federal return.
Fun story that had nothing to do with OP, and I kinda just went with it...sorry.
Branden