I completely agree in theory and I'd like to say I'm positive I would react appropriately in such a circumstance, but I remember a time when our one teacher - I might have told you this - had two kids stage a fight to prove a point. The two of them started goofing off before class, getting up in each others' faces, and everyone was laughing in the way that people do when there's mild violence in the offing; I think I was reading a book and not really paying attention. And then the "aggressor" kid started slamming the "victim" against the wall and he was going "ow, fuck, stop it" and looking scared, and no one's attitude changed! Half the room was still kind of going ahaha and the other half was ignoring it. And then the kid fell down and Mr. Heun came in and went "Why is no one helping him?" and there was dead silence. It was really sobering. You can be completely convinced that you wouldn't stand around when you saw something like that happening, and then... do it anyway, apparently. I like to think that it makes me check my reactions more, now.

VERY MUCH SO.