Why would anyone think computer databases weren't being checked when they process through what is in essence a U.S. border? I guess that is why they are criminals - too stupid to realize what CBP does.
A friend of mine spent time in Japan and when he flew into LAX for a visit home, he was detained and spent a tense few minutes in a room with other detainees while they cleared him. It seems his name matched someone with a warrant. Good thing he had a recent federal background investigation for working nuclear power on file. Life is tough for a man named James Smith!