Who is ENFORCING the rules?!? You would think that with the prizes being offered there would be no funny business...if someone wasn't happy it could be ugly! The legalities would keep me from ever running a contest with prizes like this. There would have to be verifiable complete impartiality or, like I said, it could be horribly ugly when it came time to disburse prizes.
As for me...I did this 'cuz I wanted something new in my portfolio

Everyone did a fantastic job...there's some real showpieces posted there
