public function CheckToDelete(&$oDeletionPlan)
 {
     if (MetaModel::GetConfig()->Get('demo_mode')) {
         // Users deletion is NOT allowed in demo mode
         $oDeletionPlan->AddToDelete($this, null);
         $oDeletionPlan->SetDeletionIssues($this, array('deletion not allowed in demo mode.'), true);
         $oDeletionPlan->ComputeResults();
         return false;
     }
     return parent::CheckToDelete($oDeletionPlan);
 }