Sorry for offtop, but who does check the certificate and its existance (in what step)?
In Russia, we have following pipeline to "legalize" its usage:
1. Get some kind of a certificate, that it works correctly (now, some commercial organizations also can do this certificate). They must check that lights match the standard, there are no splits in glass near driver, etc.
2. Having this certificate (it is called diagnostic card), the insurance company sells you an insurance policy.
3. Having the insurance policy, you go to the police station, and they check VIN, documents, and give you number plates and a document verifies, that the car is registered on you.
What is pipeline in the Australia?