Here is something to remember, Americans. One of the effects of the Republican's long war on the U.S. government has been the semi-gutting of the IRS. Its ability to audit people has gone way down (although audits of rich people have been reduced more than audits of the middle class). Firstly, you have to earn quite a bit of money to be liable for U.S. taxes (~100,000 dollars). Secondly, I believe that what you pay over that is a marginal rate. Thirdly, despite FATCA, the IRS's ability to come looking for you is minimal; and they know that people who are really dodging taxes are not in Canada, they're in the Cayman Islands, Panama, and Singapore.
And to the good name of the IRS, I have never heard of anyone being assessed for a FATCA penalty in the absence of unpaid taxes. In other words, the penalties are not applied to all violators, but to violators who benefit from their violation. It's not the catch-all bogeyman some people claim.