I found this comment in the GC documentation. What does it mean?
"It is suggested to use the underscore (_) before the callback name. This is because if you add the underscore at a function in your Controller it is not accessible from the URL. The private and protected method are not accessible from the $this so be careful to not use callbacks as protected or private methods."
Is the use of THIS the reason that add_email callback doesn't work?
function add_email($post_array){
$post_array['email']=base64_decode( urldecode( $this->session->userdata('userid') ) );
return $post_array;
}