The new angle to the media now is sting operations to expose crime. Investigative journalism is not born with TV news channels and there were incidents that led to large-scale reform of social and legal structures after exposure of some social practices that are detrimental to the larger interests of the society.
Invading privacy to expose specific issues is prima facie wrong because the behavior of the people involved in the expose is not natural. They are motivated to commit a crime or present misdemeanor and that is being showed as a crime.
The sting operations are by and large not news because the topic covered is often very narrow.
The exposes now being taking place about local doctor demanding bribe or a government official demanding bribe or misbehaving with public are acceptable stories because the people getting are public servants and they have to be transparent in conduct of their duties.
One important angle to this is most of the exposes of public mismanagement and bribery take place at the levels of section officers and below who are more susceptible to this because of their economic conditions in the fragmented society. The expose does not cover a wrong decision of an elected representative to locate a public place in a particular area because he or his family members possess a large piece of land around there and this public place can boost the real estate value of the place leading to good profits for him or his family.
Try catching up people who are not public servants and who do not argue greatest public manners and tempt them with basic temptations is un ethical because if you put yourself in the shoes of the person getting exposed and you cannot guarantee better behavior.