Not Deleting Cookie?

[MySQL_Narb]

The below code validates cookies for my website:

 

       //VALIDATE THE COOKIE
       //makes sure the user doesn't manually
       //change their cookie to something that doesn't exist
       if(isset($_COOKIE['user']))
       {
           //query to check if their IP is banned
           $this->database->processQuery("SELECT * FROM `banned_ips` WHERE `ip` = ? LIMIT 1", array($_SERVER['REMOTE_ADDR']), false);
           $results = $this->database->getRowCount();

           //let's make sure that their account isn't banned
           $d = $this->database->processQuery("SELECT `acc_status` FROM `users` WHERE `cookie` = ? LIMIT 1", array($_COOKIE['user']), true);

           if($this->database->getRowCount() == 0 || $d[0]['acc_status'] == 0 || $results >= 1)
           {
              setcookie('user', null, time()-2147483648, '/', $domain);
              die('DID');
           }
       }

 

However, upon entering a random cookie (meaning I'm logged in as nobody, but still logged in) - the above code does reach the "DID" line, but never deletes the cookie.

 

This allows users to login as...nobody, but still ineract as if they are a user. This code is suppose to help prevent that. But it's still possible, why?

[Pikachu2000]

You're only checking to see if the user is banned if the cookie is expired/missing? What happens if the user changes the time value?