I suspect 2 things. 1) Being Australia, the laws required it to be actually a competition and not a "chance for a chance for a chance". 2) Being 30 years ago,

I suspect 2 things. 1) Being Australia, the laws required it to be actually a competition and not a "chance for a chance for a chance". 2) Being 30 years ago, there is a less of a chance that people were simply trying to rip you off.