Does it happen? Sure it does. It happens in any kind of exams. People can be lazy or nervous and they’re guaranteed to come from all sorts of different backgrounds with varying degrees of pressure & expectation on them, so i’d go so far as to say it’s ‘normal’ to come across cheating on the law of averages in any large group… just look at society as a whole. Government. Builders. Bankers. The kind of people that cut corners for short term self gain. Of course not all of them but since about 2008, they’re all usually tarred with the same brush.