<p>Perhaps the middle ground would be to go to the professor & tell him/her that, without naming names, you are aware that cheating is going on, and that he/she needs to do something to address proctoring in the future.</p>
<p>When I was a teaching assistant, I suspected cheating going on. So I made up an “A” & an “B” version of a test. It was easy to spot the cheaters who copied their neighbor’s answer that bore not relevance to their own test. Afterwards, no messy confrontations nor time-draining disciplinary committees. </p>
<p>One of the cheaters even had the chuztpah to come to my office hours to complain. Lol at her expression when I explained that she wrote in the “A” answer to the “B” test.</p>