But as a teacher you certify that someone learned something, which is why people get a bit of paper at the end of school/university. So if you don't even try t

But as a teacher you certify that someone learned something, which is why people get a bit of paper at the end of school/university. So if you don't even try to stop people from cheating you end up doing a disservice to those who do, as you devalue that bit of paper.