Aussie (or at least NSW) big brother supposedly has us covered every which way.
In NSW they stopped issuing Registration stickers (our equivalent of a tax disc) last year.
The system is apparently policed by the myriad of fixed and mobile cameras on police cars. The latter can read loads of number plates in minutes and presumably as these are checked electronically at HQ, infringement notices are issued. Now whether this works I don't know.
But I do know that the bus lanes are policed in a similar manner and if your car doesn't have a bus number plate (separate numbering series here), you will get an infringement notice in the mail.
Since we have this system, I don't understand why we have to have an electronic toll tag for our toll roads as the cameras similarly read the number plates.
Whateva! It's no longer sporting!