AIBU to expect parents to keep an eye on children at the park?

[Stressedoutmummyof3]

My pleasure for today. Even if you know your child is an angel who would never misbehave please watch your child at the park. Or at least be somewhere near the general play area.
Today girl of about 6 being an absolute brat and really trying to wind DS up. I watch him so I know what was going on but I actually had to speak to her as I couldn't see any adult who might be watching her.
Maybe it's just me, maybe I'm over protective because of his additional needs but I'm surely not unreasonable to think you at least keep a vague eye on your child in the park?

YANBU. Those are parents who think they're doing gods work by taking their kids to the playground and are now nowhere to be seen, either glued to their phone or talking to another playdate mum. No point trying to take things in your own hands. I tell DD those are "feral kids" and she knows that as soon as children she doesn't know start to act unpleasant and clearly have no parents supervising, she just needs to avoid them or remove herself from the situation.

More like that than not at soft play and park, these days. And some of them fuss about kids being in photographs, or go on about stranger danger-but they're the biggest danger. And then we wonder why their kids cause such trouble at school.

It's not just the fact she was picking on DS but what if she'd hurt herself or someone had taken her? DS can't enjoy a lot of activities and it annoys me that one of the things he can enjoy was spoiled because some parents can't be bothered to parent.