Also if you allow different people to use different materials, it could give you very interesting results.
for example, the organizer could publish a list of all the results, with the method / materials used to hone the razor, but without the names of the honers.

This would give use an idea of how different stones compare to each other.
I know that this is hardly a true scientific test, but it could be one of the nice outcomes of this contest, and to be honest, this would come the closest to a double blind comparative study that I have seen so far.