It's true "public people" don't have to have signed a release because these pictures are considered "news" just as a news photographer doesn't need to get a release. Paparozzi are therefore put into the same legal catagory as news photographers.
But, you couldn't take a picture of a "public person" and sell it to an advertising agency or stock agency to be used for an ad. That would require a release. Because you are now leaving the "news" arena and entering the "model " arena.
I think if you were to wander around and take street pictures and not get releases and then at a later date you decided to do a book, that you would then need the releases to be published.
The only way Cameron Diaz can stop the photographer from making money off these pictures(because of a "reasonable belief of privacy") is by saying there was no release signed. I'll still bet at a later date that they'll show up on the internet or somewhere else because of all the public interest that has been generated. It's just that the photographer won't get anything for is trouble except perhaps a jail sentence for extortion.