Andrew, I totally agree with u. 100% It's indeed very bothering when kids are rude and let's admitt it, kids here in Qatar excell at being rude. No ofence to anyone, just my humble opinion based on what I've seen and experienced myself.
But no, I wouldn't go and tell the parents in their face u know, ur kids are bothering me, it's not my way, I would probably try to ignore. Especially if they are not disturbing too much, I think we can be more friendly, the world lacks more smiling faces.