I'm not from the US, so again, this is only what I heard from a colleague who's from there... He said to me that he had a chat with his banker here (it's a Singapore bank) and he was told that the bank is obliged to submit to MAS all the interest / gains paid to US citizen account holders. That sounds like big brother monitoring everyhting here - don't know if they are giving away info about tax as well...
Funny though (and lame as well) if they really give this kind of info to US govt since the SG gov long dispute with Indonesian government is about those hot Indon money lying here... And they cite it's matter of 'sovereignty' that Singapore doesn't want to share information with their neighbor about this!