I'd prefer if a parent were to submit the scenarios for them and say that it's for underaged player Jon Doe. If the scenario was insanely similar (as in directly copy and paste words or just change the wording a bit) to one I've seen on the net or WotC created (and I have nearly all if not all of the printed ones) then you would be disqualified. But we realize that there are only so many different things you can do with the battle of Hoth (for example) if your scenario shares some similarities with another no a huge deal. WotC has some of their site but there isn't a place with a bunch of fan created ones that I know of. Also, if this comes up I do plan to talk to the person who submitted a scenario before automatically disqualifying it. Give him/her a chance to tell his/her side of the story.