The Importance of Planning – PRIOR to Renouncing, Relinquishing or Abandoning
International tax law experts who specialize in a particular area of the law, have a fairly good understanding of the importance of tax planning. The reason is simple. The law is complex and without planning, 
laypeople can often cause very adverse tax consequences to themselves and their friends and family members (in the case of tax expatriation) without understanding the full implications of the law.
“Tax expatriation” in the U.S. is particular complex for several reasons:
1. The general rule is that there is an immediate income tax payable from the “mark to market” taxation rules on unrealized gains. See, Part I: Common Myths about the U.S. Tax and Legal Consequences Surrounding “Expatriation”
2. If a tax is recognized under the U.S. tax law, the only way to discharge the liability with the U.S. federal government is to pay the tax owing. The IRS generally can collect an income tax owing against a taxpayer who lives outside the U.S. indefinitely, as the 10 year collection statute does not apply when the individual outside the United States for a continuous period of at least six months. See, IRC Section 6503(c). More on this topic in another post. In other words, the IRS can “forever” pursue the collection of the “expatriation tax” against USCs and LPRs living outside the U.S.
3. It is easy to fall into the general rule of expatriation, even if the taxpayer would not otherwise be subject to income taxation. See, Why “covered expat” (“covered expatriate”) status matters, even if you have no assets! The “Forever Taint”!
4. The friends and family of the “covered expatriate” – i.e., the former U.S. citizen and long-term lawful permanent resident can be subject to U.S. taxation during their lifetimes, even if they also live outside the U.S. See also, some of the consequences of being a “covered expatriate” – The “Hidden Tax” of Expatriation – Section 2801 and its “Forever Taint.”
Each of these points help demonstrate the need for planning prior to running to the U.S. Department of State and completing and filing the following forms when you take the oath of renunciation:
See, Documents to Request the Consular Officer When Renouncing U.S. Citizenship
At the end of the day, if the individual lives outside the U.S. and does not travel to and from the U.S., it may be practically very difficult for the IRS to collect on the tax judgment owing if the individual has no assets in the U.S. There are legal means and steps the IRS can take in an attempt to try to collect U.S. taxes on overseas assets.
For a further discussion on collection of taxes overseas:
See, U.S. Enforcement/Collection of Taxes Overseas against USCs and LPRs – Legal Limitations, and
Ideally, a former U.S. citizen or long-term lawful permanent resident will wish to avoid all of the potential tax and collection issues, by engaging in thoughtful and strategic planning prior to their renunciation of U.S. citizenship or abandonment of lawful permanent residency.