I agree completely and the bolded statement in particular.I agree that since the parents have been talked too and not responded in some definite fashion, that's a poor (and very un-neighborly) decision on their part. Kids can have a lot of fun and learn boundaries and respect at the same time. The two are not mutually exclusive. The parents could have used this issue to teach this lesson to their kids.
Fun for the kids is screaming in the pool. Fun for the neighbors is having some peace in their back yards. So both sets of property owners have needs and should come to a fair commonground regarding "reasonable".
My kids (and ALL their friends)had as much fun as they could stand in the backyard growing up. But the minute they encroached on someone elses peace they had to pipe down or shut it down.
I also agree on how sound can carry. This whole thing is adding up against the parents IMO.