Really? It is unlikely that today, there is anyone born in the United States that is not in some database, as having been born in the U.S. of A., which means that person is legally a U.S. of A. citizen and is legally in the U.S. of A.
Conversely, if a person is not in a database as having immigrated legally into the United States, through an authorized port of entry, with the legal documents proving that the person did legally enter the United States, but the person is physically in the United States, then it is highly likely that person violated an immigration law, and entered the U.S. of A., illegally and thus, is a criminal for having violated a criminal law.
As to "do YOU KNOW", I assume you are making a reference to a generic you, and not me personally.
I am curious. Have you ever worked in the field of law enforcement, in which you investigated violations of law, and gathered the evidence that was used to convict someone in a criminal court of law?