When I fly with my son, I remind him not to kick the seats before the flight. I will reprimand him if he does so deliberately, and make every attempt to be considerate to other passengers.

However, as any parent knows, child control is a probabilistic thing. Most of the time they are good, but sometimes, they are not, despite all attempts to the contrary. I understand that controlling my child is my problem, but if there aren't any good solutions (and you don't seem to offer any), then you are going to get annoyed. Sorry about that, I feel badly about it, but not badly enough to tell my kid he can't go see grandma because he might act up and some guy might be annoyed if it happens.