Yeah it's Aussie, Macca's (McDonald's) always has these silly little promotions. The chances of winning anything decent are very slim. Most the time you win a free small fries or coke ect as an instant win and the large prizes tease you with two of the three needed. I highly doubt you will find a scratchy card as most people would have left them in their cars and throw them out when cleaning the car.
For about the past 10 years or so they have been promoting the Monopoly contest every year. They're just peal-off stickers of properties on the cups and fries ect. Once again the chances are ultra slim of winning. Basically you need a full set of a property type however in each set there is always one that's impossible to acquire. Once again people end up with a crap load of these tickets in the cars then throw them out when the promotion ends.
It's like gambling on a slot machine, you keep getting two of the three needed so people keep pouring money into it. Maccas keeps doing it because they make so much money from it.