public function getEmail()
    {
        // If staff, return null, we don't know who to email
        if ($this->getSurvey()->isTakenByStaff()) {
            return null;
        }

        // If we have a relation, return that address
        if ($this->hasRelation()) {
            if ($relation = $this->getRelation()) {
                return $relation->getEmail();
            }

            return null;
        }

        // It can only be the respondent
        return $this->getRespondent()->getEmailAddress();
    }