Yeah, it wouldn't really stop anyone from making a simple change, removing the copyright and then claiming it as their own. However, since I only made these a few days ago, and from the sound of the email I got, the actual designs have been in the works for a while, so I doubt it would have really mattered.
Plus, if someone did make it public they used my design without my permission, I have the original photoshop .psd files, which I never distributed, so I could definitely make a claim that they were my original works.
Either way, I'm just excited to see what they're going to end up going with and if I got anywhere close to it. Unfortunately, judging by last year's reveal, that didn't happen until November if I recall correctly, so we've got a while.