If you get audited, and the IRS decides your tax return fraudulently understates your tax bill, you are in really big trouble. You will be hit with a penalty equal to 75% of the understatement. Plus you will be charged interest. And you could face criminal charges and possible prison time. In the next few years audits of expatriates and form 2555 (foreign earned income exclusion) will increase substantially due to recent discoveries about how many such forms were incorrect and were being filed by expats not eligible for the exclusion.
Committing tax fraud takes some work, because it goes beyond simple ignorance of the tax rules and regulations. You have to intentionally do really bad things like keep two sets of books, alter or destroy documents, hide unreported income overseas, or fail to report income from illegal activities (this is not a complete list by any stretch). Bottom line: You can't commit tax fraud without knowing it.
Anyone accused of tax fraud should hire an attorney who specializes in big-time IRS problems. A CPA or Enrolled Agent can't provide the equivalent of the attorney-client privilege, and those accused of tax fraud will need that privilege. Also, non-attorneys are not competent to deal with the criminal charges that will often go along for the ride with tax fraud cases.
