For cases where one sensibly used uuids, I don't see natural keys being an alternative. What's e.g. the natural key of an order reference that should be accessi

For cases where one sensibly used uuids, I don't see natural keys being an alternative. What's e.g. the natural key of an order reference that should be accessible without auth, when the key shouldn't allow enumeration and that should be allocatable without a single point of coordination?