Well, if seat-kicking, screaming, and running are really the only options, let's just hypothesize a bit: suppose the mother knew if she could prevent her child from these activities, she would receive $10,000 at the end of the flight. Would she figure out a way to prevent the behavior? I suspect yes, in 99%+ of cases, because as I implied above, it seems to be a matter of parental motivation in most cases. It certainly is a lot easier for the mom to not tire herself by figuring out ways to otherwise amuse the child, or to discipline the child who is old enough to know the word "no", when there is no loss to the mother for letting the behavior continue other than maybe feeling "bad." I remember flying as a young child and being forced to behave -- part of my mother's strategy used to shut me up was to bring along a big kit of toys and games for me to play with in flight, and stern words (and threats of more) would follow if I still didn't behave. But maybe that was an old-fashioned 20th century approach.

I have much more sympathy for the mother with the screaming baby, where the baby is way too young to understand "no" or to be disciplined in any way, and is just very uncomfortable even when dry or fed, so it screams. But I'm not sure at what age the child is old enough to understand "no" well enough not to kick etc.

A big reason to try and fly F, if possible.