Australia has become a police nanny state - its one of the reasons I left.
It is possible to beat the police on these traffic matters (I have done it many times) but you really have to know what you are doing. Being a lawyer helps. :-)
The problem, as you note, is that there isn't enough money in it for lawyers to act for clients on traffic matters, so the Police and Courts get away with it.
What's needed is a class action by motorists against the Police on a legal flaw that has affected many people.
Also, stop voting for governments that think their job is to be a nanny.