In case of emergency, whether the kid is lost or has gone non responsive to calls or texts, it can be important to parents who want to be able to know where to find them in those situations. Furthermore, there are some parents who are simply strict and want to track their every movement; which could be very intrusive, make the kid paranoid, and even ruin the parent-child relationship. That’s my take on it.
This changes when Atticus shoots the mad dog. They find out that he is a sharp shooter and was infamous in the county as one-shot Finch. They were now proud of their father. Jem is confused that his father has kept this a secret and at first wants to know why Atticus would not be proud and brag about this ability.
The reason Jem won't allow Scout to brag about Atticus's talent is because he wants to be a gentleman like his father and understands that having the ability to shoot beings is not something to take pride in.
That is because a theme is the most basic concept explored in a piece of fiction, like the battle of good versus evil, which can be explored in million ways.
