US tourist visa if I lived illegally

Pedro writes, "I came to the United States as a child over 20 years ago with my parents on a valid visa but never left.  Since then I have lived here, gone to college, but now that my life is going by and I see no hope for legalizing my status, I do not want to waste my life working illegally in Mexican restaurants washing dishes.  In my native country, I have been offered an executive job due to my excellent education and bilingual skills and I have decided to take that position because that way I no longer have to live in fear as an undocumented immigrant, I can travel the world, and have a family.  I will also use my American education in my job.  But before I leave, I want to know what will happen at the airport?  Will ICE harass me?  Will they stamp my passport with a 10-year ban?  Will I be fingerprinted?  I have no criminal record of any kind and have never interacted with US law enforcement of any kind.  Will I be able to visit the United States as a visitor later on?

What to expect at the airport if an undocumented immigrant is returning to one's native country?  While the United States law enforcement does have the authority to detain and arrest anyone who is in the country illegally at any place (and it is common for Border Police to detain undocumented immigrants leaving the US for Mexico to make sure they leave after fingerprinting them because that means they will not be able to return legally for ten years), unless something goes terribly wrong, you will be able to leave without any interaction with law enforcement.  You should have a valid passport if you are returning to your native country and a visa (if needed) if you are traveling to another country.  You will only interact with airline staff (though you can minimize that interaction by doing most of the paperwork at the airline website and at the kiosk in the terminal, though, someone will check your passport at least twice, at the time of dropping off your bags and then before boarding the international leg of your flight).  In rare cases, the airline agent might question you about a US visa, but you can simply tell them that your passport is new or you lost some documents and at that point they will figure out that you are illegally in the US and leave you alone (there really is no system to do anything).  The TSA agents will merely check your passport and boarding pass and it is unlikely that anything else will happen.

What to expect when you apply for a visa to visit the US?  If you have ever lived or traveled to the United States, you must honestly answer this question in the tourist visa application.  Additional questions maybe asked if there is a visa interview at the US embassy/consulate.  The State Department has other ways to find out if you ever lived in the US because it has access to many databases.  Chances are your name will pop up somewhere if you went to school/college, worked, paid taxes, applied for a driver's license, etc.  That means that even if you apply for the visa after 10 years, the embassy might deny the visa since you will be considered high risk and more likely to overstay.  However, if you build a good life in your native country, have evidence to prove your strong ties like employment, property, family, etc., you might be able to receive a tourist visa.