Many people have a different way of performing certain task. I feel that you should perform the job accurately that you are hired for. I don't believe that people work harder while being observed. Work ethic to me is something that is learned and can be perfected.
The Hawthorne Effect however, has proved differently. This study showed employees perform their jobs above and beyond while being knowingly observed. I feel that while such study is important to companies for accurately recorded data or increased productivity, however, I think such routine can enable people with natural work ethic be overlooked.
I can't say I disagree with the data gathering techniques that increases productivity during observation, however, I do feel people should be responsible for conducting and achieving what is expected of them anyway in a work place.