Signing the key is the important part. Proving that the key was in fact created by the people it was supposed to be. (I think they key does have to be kept secure, which could be done by using a one time pad. Theoretically unbreakable.)
Indeed! And I'm not even thinking about the communication channel as much as...Verisign. Not picking on them, but it's just a single, US based organization.
Can someone explain how this step doesn't invalidate all of the hours of ceremony and procedure?
"Later Okubo will transmit the key on a secure channel to Verisign and this signed key will be made live across the internet."