Well, if you are here with a green card, or student visa, or are here with an H1B certificate working for a company that arranged your legal work, or if you are a born and raised citizen of the United States or a US protectorate such as Puerto Rico, totally entitle to live in continental United States. It becomes pretty important. But it doesn't mean anything if they don't check/don't care and you will never see a judge to prove it.
People in all these categories have been arrested by ICE and Homeland Defense. They need the numbers, and mistakes are made. We definitely know, if they get as far as being sent to an El Salvadore prison camp by mistake, you ain't coming back, even if mistake is admitted.