whats the disadvatge of ethical principles: protection from harm?

[ok]

This is about the role of research.
For positive I wrote

"The strength of this ethical principle is that researchers have a set of rules to follow while approaching individuals or researching , also the person being questioned will feel comfortable with answering the question knowing they're identify will be save and wont affect they're private life.

Could any one tell me the disadvantage?

If you can can you explain the advantage and disadvantages for

Ethical issue :role of media
Implications of research: Reliability
Legislation:Human rights

In research.

Thank youuu