You can detect it. You interview the student about their paper. If they don't know or understand what they wrote, then either they cheated or they may as well h

You can detect it. You interview the student about their paper. If they don't know or understand what they wrote, then either they cheated or they may as well have cheated because they didn't learn anything. If you have enough money (they do), make the interview part of the assessment for all students.