The idea behind throwing the exception was to give the user a clear indication of where to start debugging. However, I am not particurly against returning `null` or `''`. The reason for this change was that if a user were to call `$this->getSession()->getCurrentUrl()` without having started a session, he would receive a PHP 'method called on non-object' error...which can potentially be quite cryptic if you don't know where to look.