Yeah, I also encourage the kids to tell the "offender" (whether it's real or not) what they didn't like/appreciate. Around here they tatle tale for ridiculous things. Like x is singing loud. If it's like that I say "oh yeah? How nice!" But, of course if it's dangerous or not nice, that doesn't work
It also in better received if another child is saying "hey I don't like what you're doing. Stop" than if it comes from me. And it empowers the "vicitim" And if it's not true, well then they won't randomly tell other kids to "stop"