Friend of mine worked in an adjacent industry (not TSA, not in the US even, for a contractor doing "mystery passenger" testing for major airlines I believe. Man

Friend of mine worked in an adjacent industry (not TSA, not in the US even, for a contractor doing "mystery passenger" testing for major airlines I believe. Many countries require airlines to do their own checks at departure for international incoming flights, and levy big fines if a traveler with invalid documents is let through, so airlines do care about this a great deal. He once tried to travel internationally without a Passport / ID, I don't remember if this was within Schengen or not. He had a sob story about his mother dying and him trying to get home to her funeral. He was let through, partly because of people believing him, partly because of incompetence and people just not checking. A good few employees were sacked because of this.