Having recently asked a question which clearly fell foul of the above rule, I would like to point out the difficulties in policing it and see if any improvements can be made in this regard for new users.
Firstly, the policy isn't actually written down anywhere, I've been referred to the how to answer and how to ask sections, no-where does it say that your question/answer must refer to a well-known philosopher.
Secondly and most importantly, whilst those who work in Philosophy might like to think otherwise, there is no objective measure of what constitutes a "philosopher" other than who other philosophers choose to include in that group (consider how many philosophers actually wrote stories, yet not all stories are philosophy texts). This leads to a paradox in which in order to ask a question you must already be aware that there is an answer written by one of the accepted philosophers. If you are already aware of this, why ask the question?
The reason other sites do not have this problem is not because they are more strict it is because it is immediately apparent to the layman that, for example, Douglas Adams is not a physicist, nor a chemist, nor a computer scientist etc. Whether or not he's a philosopher can only be decided with a pre-existing knowledge of the field of philosophy so that one can trawl through the existing canon of accepted texts to find he isn't there.
Consider Physics.SE. Anyone could ask "what is the rate of acceleration due to gravity?" and anyone who knows what it is could answer (without, I might add, having to preface their answer with "Accoring to Newton..."). Questions like "what is the history of scientific thoughts about gravity?" might well be considered meta, or even off topic - matters for History.SE perhaps. With Philosophy.SE, it seems like you're asking only for the second type of question, not a question of actual philosophy, but a question about the study of philosophical questions by a select group of people.
You therefore risk setting up a site in which laymen cannot ask questions without considerable prior knowledge of the membership of this select group (which is very much against the Stack Exchange ethic).
Basically, you have to accept that philosophy as a academic subject is weakly (and in some case arbitrarily) defined. As such a Stack Exchange format site on the subject is going to have to work slightly differently from other sites on more objectively defined subjects.