code: public function validate() {
  
  		$result = parent::validate();
  		$this->Title = strtolower($this->Title);
  		if($result->valid() && !$this->Title) {
  			$result->error('"Title" required!');
  		}
  		else if($result->valid() && FusionTag::get_one('FusionTag', array(
  			'ID != ?' => $this->ID,
  			'Title = ?' => $this->Title
  		))) {
  			$result->error('Tag already exists!');
  		}
  
  		// Allow extension.
  
  		$this->extend('validateFusionTag', $result);
  		return $result;
  	}
docs: Confirm that the fusion tag has been given a title and doesn't already exist.