By default if we restrict a field with field permission in cck , if user role restricted user can not see the field and "required" property of field not efftected in node submit.
With text , etc field this is ok but when I did this work on image cck field ( set it required and setup restriction in field permission ) in view is ok (#access seted false ) , but when I want submit node get me "field is reqired " . I test it in raw drupal with minimal modules installed.