Add Permission to view chats, but not participate

A client of mine wants to give anonymous users the ability to view chats as they happen, but not participate in them. The user would have to log in to participate, essentially removing the ability for guest comments.

I have achieved this with some hook_form_alter()s, but I wonder if this is a feature anyone else might like to have.

My code is below. It could obviously be achieved differently if it was included in the module. You would also likely want a hook_update_n to give everyone who has "access chats" permission the new "participate in chats" permission.

<?php

/**
 * Implementation of hook_perm().
 */
function mymodule_perm() {
  return array('participate in chats');
}

/**
 * Implementation of hook_form_alter().
 */
function mymodule_form_alter(&$form, $form_state, $form_id) {
  global $user;
  switch ($form_id) {
    // Hide chatroom buttons from those who don't have access
    case 'chatroom_chat_buttons':
      if (!user_access('participate in chats')) {
        $form['chatroom_message_entry_box']['#access'] = FALSE;
        $form['chatroom_message_entry_submit']['#access'] = FALSE;
        // Show a login link if they are not logged in
        if ($user->uid == 0) {
          $node = glodigital_parse_menu_node_object();
          if ($message = variable_get('chatroom_chat_login_text', t('Please !login to participate in this chat.'))) {
            $message = str_replace('!login', l(t('log in'), 'user/login', array(
              'query' => 'destination=node/'. $node->nid,
            )), $message);
          }
        }
        // Show a message saying they don't have access
        else {
          $message = variable_get('chatroom_chat_logged_in_text', t('You do not have access to participate in this chat.'));
        }
        if ($message) {
          $form['chatroom_message_login_text'] = array(
            '#type' => 'markup',
            '#value' => '<div id="chatroom-chat-buttons">'. $message .'</div>',
          );
        }
      }
      break;

    // Add chatroom settings for users to view but not participate.
    case 'chatroom_admin_settings':
      $form['chatroom_chat_login_text'] = array(
        '#type' => 'textfield',
        '#title' => t('Login to chat text'),
        '#description' => t('The text to be displayed to anonymous users who don\'t have permission to chat. Leave blank to display nothing.'),
        '#default_value' => variable_get('chatroom_chat_login_text', t('Please !login to participate in this chat.')),
        '#size' => 60,
      );
      $form['chatroom_chat_logged_in_text'] = array(
        '#type' => 'textfield',
        '#title' => t('Unable to chat text'),
        '#description' => t('The text to be displayed to logged in users who don\'t have permission to chat. Leave blank to display nothing.'),
        '#default_value' => variable_get('chatroom_chat_logged_in_text', t('You do not have access to participate in this chat.')),
        '#size' => 60,
      );
      break;
  }

}
?>

Thoughts?