Seems your plates work very differently in australia, interesting! I would never have thought - I'll mark it as my thing learned for the day I know here often the plates for our vehicles are made by prisoners - perhaps someone conveniently made an unofficial duplicate. It wouldn't shock me anyway, not in the States. Can't comment on the theft bit at the moment, as I'm too stunned to learn that you own your plates for life and you have different kinds (perhaps the different kinds are like how ours work by state).