I agree with Tiptopper that his approach offers a longer juding period, which is better.
The one disadvantage is that if a writer reads a great story, and is inspired to write his own take on it, then that sort of water downs the first guys entry a bit. So if you have one great story with an Energizer Bunny joke on it on day one, you could have 50 stories with the same joke at the end.
I know there were elements of Tiptopper's incredible CAT'S CURIOSITY that I loved, and which I incorporated into my next story. Building on great ideas is a good thing, of course, and since both of our stories were like 7,000 words plus it was hardly noticable. It might be more notiicable in the confines of a story contest, though.
This isn't THAT big a deal, and I don't mean to make it sound like everyone's ripping each other off (they're not) or we're in some sort of steel-cage deathmatch, because I know this is just for fun. I'm just guessing that this MIGHT have been the moderator's original motive for not showing the cards until the end. This is a VERY narrow and minor point, but a point nonetheless.
I think Tiptopper's stories are awesome, by the way, and if you're reading this right now, stop and go back and read CAT'S CURIOSITY, which is way better than this post!

Now I have to get back to my new story, BUNNY SPANK!