Parents are responsible for setting limitations for their children. Tell children exactly what you expect and when you expect it. Otherwise they will feel guilty every time you catch them watching a show. Lack of clarity causes many unnecessary confrontations. Children feel pressured to live up to their parents' expectations, but if they have no clue about those expectations, they become frustrated.
Nobody wants to live in an atmosphere where expectations are undefined and punishment is quick.
When setting limitations for children, be specific, clear and consistent. This is both unfair and unhelpful. When parents fail to explain why something is not allowed, children grow up thinking there are no reasons. Without reasons, it follows that there is really no need to obey, especially when the parent is no longer around to monitor behavior. As parents, we need to make the effort to think about why we set certain limitations.