This flaw came to my attention when reading the comments to this post http://e621.net/post/show/103282/anal-comic-daddy-s_scent-dragon-gay-glued_on_penis
This is not meant to cause drama, but point towards a legal problem. See the Takedown Policy:
"We will honor art removal requests ONLY from the legal copyright holder of the art. Simply commissioning artwork from an artist does NOT automatically transfer copyright of that image to the commissioner."
You are neglecting character copyright here. Sorry, but there are even law cases that confirm it. See http://www.suite101.com/content/comic-book-copyrights-in-gaiman-v-mcfarlane-a102584 and in general http://www.publaw.com/fiction.html
To sum it up for you: The artist _and_ the commissioner both have rights on commissions and _both_ would need to agree for the art to be uploaded _anywhere_. Or do you really believe that somebody who pays for art to be drawn in the way he/she imagines it really has no rights on the creation?! The art would not have been created in the first place, when the commissioner did not have the idea and commissioned it.
It is common practice on the fandom, that artist and commissioner both can upload the art without asking each other for allowance in the first place, but that does _not_ apply to anybody else. It is not a legally defendable common practice that just somebody takes art and reuploads it at random.
Sorry guys, but when Varka really plans to charge for premium accounts here then, believe it or not, that is a felony and I really wished I was exaggerating with this statement. e621.net has nearly no own content. Only "unapproved uploads".
Anyway, I made my point clear. Just found out about this site recently and now I am curious if such a topic will simply get deleted or lashed by clueless folks.
Updated by Burninghart