I'd tell her the next time they do that you're calling the cops for trespassing. She'll get the message when you actually do it. I hate parents who make excuses for their kids' bad behavior and blames everyone else.

I would put cactus after your two meters fence. Or security camera. If you can catch them on video, 1- you will be able to prove your innocence if there is an accident, 2- you sue her for trespassing if you want

Build a wall of broccoli and books around your pool and kids will avoid it like the plague.

Property owners aren't responsible for trespassers getting hurt, unless you have things in your yard that are specifically designed to cause harm. So, fence or no fence, it's her problem.

Sounds like she's just at her wits end trying to keep her kids in line. Often trying to enforce rules for your kid is harder on the parent then it is on the kid.

get a tree trimming company to cut the tree back so it doesn't overhang your fence. problem solved

unstal razor wire? ( please do) please don't then she can blame you for that

Oh great, another one of those parents who swears their kids can do no wrong... they need a good face slap of reality.