Maybe the parents were UA employees as well and the kids were gate-agents-in-training!
Just KIDDING.
But I'm sorry to hear about your flight. As you probably know, this "Kids in First" (or anywhere on the plane, for that matter) has been discussed and discussed here. I'm on the side "Screaming Kids Don't Belong in First, Business or Economy With Parents Who Don't Care" - they don't even belong on Greyhound!