It’s simple. Right section, right row, right seat number.
Trade seats with the family flying with children so they can sit together, even if it is for a middle seat. Don’t be selfish.
Or stupid, either. Think this through: Do you want to be the one to comfort the hysterical four-year-old — to be the scary stranger trying to soothe, entertain, and take full responsibility for them? No, you don’t. And you shouldn’t.