adding on to this, I had an English teacher pull a similar stunt.
We were all doing some classwork, writing an essay or whatever the fuck. Suddenly she looks over at a guy and says "Why are you looking at your friends paper? You trying to cheat?"
The guy kinda froze. This guy was a standup guy. Super friendly and super honest, like, the last person you'd think was cheating. So he says "no i wasn't looking"
Teacher: *pissed* You calling me a liar??
At this point the guy sitting next the "cheater" tentatively says "he wasn't looking at my paper"
Teacher: *points to him* You stay out of this. *Points to "cheater" You. See me outside.
At this point the rest of us are like "wtf that came out of nowhere. I'd better be careful she seems like shes in a bad mood."
They come back in, "cheater" looking real down on himself, and the teacher says to everyone "who thinks he cheated? No one right? Cause you know him and you know he'd never cheat. And yet not one of you said a thing. That instinct you all had to keep your heads down stopped you from standing up to injustice when it was staring you in the face! So stop it. If you speak out against injustice and get in trouble it'll always be worth it"