I hate other people's children

Maybe hate is a bit strong. But I really don't at all enjoy being around large groups of kids. I've been volunteering at the school this year, and whole classes full of children always seem chaotic to me (or is it that my kid's teacher sucks?). I prefer the one-on-one tutoring I get a chance to do; and I seem to be good at it. I've even had teachers I don't yet know stop by to tell me that they've been listening to me, and they appreciate what a good job I do with the kids.

And, one-on-one, most kids don't drive me too crazy. Because I can give them "the look" and/or "the tone" of voice and they'll settle down and do what I've asked them to. That's the easy part!

But, in larger crowds, there are always the ones who are talking when they should be listening to the school concert, those who use their time on the bus to belittle and bully other kids, those who climb up the slides at the playground while others are patiently waiting in line at the top, etc. My kids can also act up, sure. But 90% of the time, they're the ones following the rules... and getting trampled by those who do not. It brings out the momma bear in me, and makes me want to smack those other kids.

Ok, so maybe the problem isn't the kids in this situation so much as it's the adults who fail to correct them. At the playground, if my kids aren't following the rules, I tend to remind them. At a concert, same thing. I spent last year's holiday concert by the elementary children steaming because I couldn't hear a large part of the performances: groups of children waiting to perform were running wild while the "parent helpers" seemed either ok with it or oblivious to it, and many of the audience families weren't exactly being quiet or polite either.

I'd had enough at the playground recently and corrected someone else's brood, when I was pretty sure the adults wouldn't notice and take offense. At what point is it ok to step in (sorry, actual parents/"adults in charge," you had your chance and didn't take it!) and correct other people's children?