Public Acess LAW

The new public access law has me wondering. According to the article on the home page information can be withheld to protect privacy and security.
Who will determine what is un releasable?
Is it up to the government agency to prove to a judge that it needs to remain private or does the party requesting the information need to prove with out seeing the information it is not privileged?
John

thanks

Thanks for the reply. On the surface the law looks like it could give transparancy tot he process and help fight corruoption. The problem is who has the word on what can be hiddne and what can not.
John