Unfortunately, three of the kids ended up in the F cabin on my LHR-LAX flight with their parents
They were pretty well-behaved after we reached cruise altitude and until we began descent...
I have to admit that I really do like the Malaysia Airlines policy of no kids in F.
Maybe - its not universal that kids are a mess all the time! Our oldest is 5 and you wouldn't know she was on a the flight. under 3 was a different story.