There will probably be a flood of expats doing that in the next while .... problem is the IRS will be right on your trail out of suspicion .... I should also add if you are in that situation and renounce your U.S. citizenship at this time you still have to file for the last 4 years as you were still a U.S. citizen.
They want bank statements and detailed statements on you investments. A rather complicated affair if you are unfamiliar with U.S. tax filings My friend gave up last weekend trying to do it on his own ... has now consulted a lawyer at a cost of around 1 grand. Our friends in Toronto have also gone with a lawyer. These people, who are Canadian citizens have never earned a penny in U.S.or income in their lives or for the last 40 years. They do not have any U.S. pension income and have not made any money from U.S. investments and do not hold any property in the U.S. .... they held on to their U.S. citizenship out of some patriotic feeling but now realize that citizenship is a curse.
I suspect this is just a money grab by the U.S. ... going after your Canadian RRSP retirement funds ... rather stupid as it is going after pennies of the working guy expat while spending $millions's in the effort.
biLL ... oh well, thought I'd just bring this to your attention ... enuf of my 2 bit rambling here.