I know I have said this before but if you give a policeman a power he will use it .... most often for reasons that it was not originally intended. They (the police) are very good at that sort of thing and will jump at any excuse to extend their reach into the lives of everyone they come into contact with.
The police need to be controlled not given an open-ended excuse to do whatever they feel like. See recent cases of arresting people under laws which we were assured were only to prevent terrorists blowing us up.