hook_webform_results_access documentation incorrect

When attempting to implement my own custom permissions hook with webform, restricting the results further, I was unable to do so with the stock module. My module looked like nothing more than so:

function nnlm_core_webform_results_access($node, $account){
  return FALSE;
}

Looking at the code that invokes this hook, we see the following:

function webform_results_access($node, $account = NULL) {
  global $user;
  $account = isset($account) ? $account : $user;

  $module_access = count(array_filter(module_invoke_all('webform_results_access', $node, $account))) > 0;

  return node_access('view', $node, $account) && ($module_access || user_access('access all webform results', $account) || (user_access('access own webform results', $account) && $account->uid == $node->uid));
}

If my hook returns false, the user will still be able to access the results as long as the permissions of the webform module allow it. Which is fine, but it would be nice if the documentation clarified that. Currently, it implies (at least to me) that I can restrict access by returning false.