I was wondering about this myself Jack but it is not necessarily a given that every state has to be as riddled with cheats as NSW - maybe they are and maybe they aren't. While cheating does not start and finish at state borders, we all know that some neighbourhoods are more dangerous than others and some families have criminal ties so maybe cheating can be more concentrated in one state.
I am not convinced it is but we do have to remember that not long ago NSW had stewards involved in cheating