I travel JetBlue.................and I have not seen hide nor hair of a first class seat. They are ALL coach seats. They always announce preboarding by saying that it is for small children, people in wheelchairs, and anyone else who needs a little extra help or time in boarding.
It's the same on all airlines here in Canada, and recently I flew to and from LA and San Fran, and those airlines (Alaska and United) had the same message about "...those needing assistance or who have small children are invited to pre-board..."
Wasn't the whole issue the fact that she was not in her seat? It doesn't take two to buckle a kid up, does it? As far as I'm concerned, the noise (screaming) is a different issue - was she even screaming? I can't remember anymore. Believe me, if I knew we were about to take off, my brat would have been in her damn seat ... anybody can say all they want about the poor little dears , but 3 yr olds have a very good understanding of what's what and how to manipulate, etc. They are NOT stupid! They understand "Don't", "No", "Come here", and "Be Quiet!" I think the blames lies squarely on mom and dad.