That is appalling. I've lived to schools, and yes playtime is noisy. So what.

I thought we'd gone too far with people moving into the countryside and then forcing farmers to shut their animals in to prevent 'noise', but our own children!

I'd tell the complainers to move.

If I knew who they were, I'd write to them and say I hope they never need these children as doctors, nurses, carers, etc. in the future.