Hide option when set for all

As per the initial feature request in http://drupal.org/node/340950 , when the content type is set to read-only for all groups in the excellent patch by rcourtna , it would be very nice to hide the option to do so for each group admin.

I did it with hook_form_alter in a custom module:

$form['og_read_only_types']['#access'] = 0;