For the SPC I have a disclaimer that gives me the permission to re-post any of the entries if they have won a position. It's just after the rules section. I wanted to cover my bases there so that there wouldn't be and problems in the future especially if a copyrighted image made its way through that the person didn't have permission to post!!
It says:
"By entering this competition you acknowledge that you own the rights to the photographs and allow for me to re-post the image should it receive a winner or honourable mention position."
So when does that Erotic Fine Art contest start :)
Soon I'm working on the Rules right now :)