I'm gonna tell you to be the bigger person here, H., and let this go. It sounds like you've made the one concession that you could under the circumstances and anything else would simply be forcing your children to not act like....well, children. And that's not fair for anyone.
I think the main issue here is that you can't stand the idea that someone has unfairly judged and dislikes you. And who can blame you? Most people want to be liked. Heck, I'd even take being IGNORED over getting chewed out by a complete stranger for no reason.
So your neighbor decided to rake you over the coals that day rather than communicate with you as one adult to another. Instead of reaching out to you in kindness and sharing her concerns, she judged you and jumped to all the wrong conclusions before dumping her list of complaints on your lap. (To be fair, though, you are also jumping to conclusions regarding HER children's activities, so I guess we can all fall into that pit once in a while.) Honestly, most of us get annoyed at our neighbors for one reason or another but good manners usually keep us in check. This woman obviously has none.
All that being said, who's problem is this really? Because it's certainly not yours. So why are you getting so hung up on it? You've got a cranky neighbor, so what? Do the best you can to keep the peace and get on with your life. You don't have to lose sleep over the idea that this lady doesn't care for you...she probably doesn't care for a LOT of people. How much power are you willing to give her, anyway?
Rather than doing something sarcastic (like warning her of impending noises), take this as an opportunity to teach your kids to "turn the other cheek" and not let negative people get them down. And rest easy knowing that, while this one neighbor might not see your true, charming self...the people you care about the most DO. And that's what counts.
So do what you can (and what is REASONABLE) to keep the peace and let bygones be bygones.
Good luck, H.. You'll probably need it. ;-)