Tracking your parents

Issue for debate: If parents are allowed to monitor their children´s activities, what happens when those children become adults? Are the children allowed to monitor their parents? And when does it become spying? These kids decided to do just that, hacking their father´s computer and using GPS to locate him and maybe even murder him. Raises the question of how far one can go with surveillance and what if it is in the interest of the subject itself such as a mentally ill family member? Technology creating more questions than answers again...