Actually I thought they DO need ID if they are 10 or over. At that age Disney classifies them as adults dont they? Therefore wouldnt they have to do the biometric scanners? If that is right then they may need ID to show the CM. But maybe the CM just takes the parents word as to who the child is.
That being said, I already went to the license branch and got DD10 an ID card made.

She said it was really cool and she keeps it in her purses wallet. It may come in handy, then again, she may never use it. But it only cost $6, so oh well.