It seems widely accepted that there are different degrees of justification for the invasion of privacy, depending on the position you hold in the public eye. Firstly there are people who hold a position of power and responsibility, ranging from national power (e.g. politicians) to local responsibility (e.g. teachers and clergymen). Secondly, there are celebrities; people who choose to be in the public eye but not because they hold a position of responsibility. The third group is ‘regular’ people, who are thrust into the spotlight through a famous relative or by an event or disaster that they were part of or witnessed.
Concerning the first group, while politicians are obvious candidates, it also includes businessmen, and, on a more local level, teachers, clergymen and policemen. The definition of privacy (according to the OED) states that people should be “free from public attention, as a matter of choice or right.” In my opinion, taking a position of power takes away from this area of privacy. It is proportional, in that at the highest level of power (politicians) your actions will necessarily be of public attention, whereas at the lower level (teachers) the majority of your actions should not be of interest to the public.