There is that feature already. When you create a game there is a drop down box that you can make unrated. Check some of the open seeks, there are some that are unrated.
And I, personally, think that is a great idea to help people get better at chess.
I was wondering if it's possible to play unrated email chess games. If it is possible, my idea would be to play with a couple of beginners and the stronger player would put comments in the chat column... like live annotation of the game. That way the beginner or lower rated player can learn as they play instead of waiting til the game is over etc. I would like the game to be unrated so that nobody loses points if the game ends in a draw or loss. It is just for mutual benefit. (Is there another/better way to accomplish the same goal online?)
What do you think?