Of course if you do phone the council and tell them "Hi, I'd like to complain about some kids laughing and playing on a trampoline", I'm pretty sure the kids wouldn't be the only ones laughing
Of course, conflating the argument to this kind of silly level to try and make out one side is being unreasonable is a little daft.
As has been said - kids playing is one thing but kids (or anyone) just constantly screeching and screaming is a little OTT.
The argument of "kids going to be kids and should be allowed to enjoy themselves".is all well and good if you accept that constant screaming and screeching means that others are being denied their ability to enjoy themselves and their outdoor space.
Does one groups right override the other's?