=== modified file 'modules/user/user.module'
--- modules/user/user.module	2009-02-26 07:30:29 +0000
+++ modules/user/user.module	2009-03-14 23:52:46 +0000
@@ -1092,7 +1092,16 @@ function theme_user_list($users, $title 
 
 function user_is_anonymous() {
   // Menu administrators can see items for anonymous when administering.
-  return !$GLOBALS['user']->uid || !empty($GLOBALS['menu_admin']);
+  if (!(!$GLOBALS['user']->uid || !empty($GLOBALS['menu_admin']))){ // If the user is not anonymous, then explain why they cannot see the page they are trying to access.
+    if (isset($_GET['q'])){
+      $redirect_args = array('query' => 'destination='. $_GET['q']);
+    }else{
+      $redirect_args = array();
+    }
+    drupal_set_message(t('This page can only be accessed if you are not logged in. Currently, you are logged in as '). l($GLOBALS['user']->name, 'user/'. $GLOBALS['user']->uid) .'. '. l(t('Log out'), 'user/logout', $redirect_args) .t(' to access this page.'));
+    return false;
+  }
+  return true;
 }
 
 function user_is_logged_in() {