/**
  * Validate a event crew form submission.
  * @param \App\Http\Requests\GenericRequest $request
  * @param \App\Event                        $event
  * @param bool                              $validateUser
  */
 private function validateCrew(GenericRequest $request, Event $event, $validateUser = true)
 {
     if ($request->has('guest') && $event->isSocial()) {
         $this->validate($request, ['guest_name' => 'required'], ['guest_name.required' => 'Please enter the guest\'s name']);
     } else {
         $this->validate($request, ['user_id' => 'required' . ($validateUser ? '|exists:users,id' : ''), 'name' => 'required_if:core,1'], ['user_id.required' => 'Please select a member', 'user_id.exists' => 'Please select a member', 'name.required_if' => 'Please enter a role title']);
     }
 }