By requiring postwork to be announced you then by inference need to have a stringent set of rules which set a boundary to what you can and cannot do to a photo. Being a member of another such website i know the problems involved in keeping to such a tight policy of "such and such is allowed in a photo at this level of competition".  Also - to get so pedantic on the subject would mean submitting originals of the photo to the team for review (so they can recreate the steps involved to check if any "foul play" has occured). They already have enough on their hands to be bothered with a challenge which is (as far as i know) only present in this forum on Renderosity and put together on the essence of "good will"...  "let the voters decide" i say...

"In every colour, there's the light.
In every stone sleeps a crystal.
Remember the Shaman, when he used to say:
Man is the dream of the Dolphin"

Rich Meadows Photography