That is just the problem - too many people do not plan ahead and/or don't stop to think that their child's loud behavior might be obtrusive to others around them. I can not tell you how many times that I have seen parents basically ignore their kids as they ran around the PC or kicking the back of the seat in front of them. A screaming infant is one thing, out of control kids is completely another and it reflects poorly on the parents. This issue is problematic everywhere in public, not just in airports or planes. My favorite story is from a good friend - he was on a flight from the west coast and the child behind him thought it was a fun game to kick my friend's seat and pull his hair when he tried to ignore him and sleep. The mom's response when asked to control her monster? He's a kid, deal with it. Luckily a FA happened to be close and was kind enough to step in and suggest that the woman change seats.

I always compliment parents of children who act well during flights and even help out whenever I can, espescially when it is just one parent.