If a son or daughter of a government agent or soldier didn't want to learn this stuff, Then they shouldn't have to but if they wanted the training, Then I don't see why they can't get the training. They could be used as spies or fighters that the villains don't see coming plus they could use these skills to outwit school bullies and attract dates.
They don't see their parents because they work all day. They might actually resent that their parents are never home and are never around.
They wake and their dad is already at work. They come home and their parent is not there. Late past 5:00 their parent comes home and wants to eat and sleep.
If by some chance the parent worked at home and was a cool parent them maybe they could teach the children some things. In most cases they will just stay home with their mom.