message: log if default fatal error
diff: @@ -151,7 +151,7 @@ template <typename M, typename T>
  T get_parameter(M map, std::string param_name, const T &default_value) {
  auto search_result = get_parameter_recursive(map, param_name, default_value);
  if (!search_result.second && log_if_default_) {
  - LOG(WARNING) << "Using default " << default_value << " for param \""
  + LOG(FATAL) << "Using default " << default_value << " for param \""
  << param_name << "\"";
  }
  return search_result.first;
  