private function isVisitorKnown()
    {
        if ( ! $this->session()->has($this->getSessionKey()))
            return false;

        if ($this->getVisitorData('uuid') != $this->getVisitorIdFromSystem())
            return false;

        if ( ! $this->findByUuid($this->getVisitorData('uuid')))
            return false;

        return true;
    }