I think that you're putting the cart before the horse! We could have items go out by quests by the hundreds per day, and make it about turning in the right items - even if you've got some in your vault you won't be at too much of an advantage. Just as a really simple example -- we shouldn't limit ourselves just because there might be an advantage, lets think about how to make that advantage a little bit smaller.

And in many cases, I'm pretty okay with there being a baked in advantage even if it doesn't pre-determine the winners. We don't get a lot of new users, so mostly people competing in these kinds of things are going to be people who've been here for at least 2+ years, we aren't typically seeing anyone start from 0.