Australian election rigged - my experience when voting

I was just voting in the Australian federal election, and something pretty messed up was revealed to me.

I go in, tell the people there that I'll take the papers and put them in the ballot box but I'm not voting. They ask why, and I say "because we don't really live in a democratic country and the election is rigged" (do you think the US is going to let a major strategic partner choose their own government on the eve of a Syria invasion?). The polling official surprises me when she says "well, there's a lot to be said for that point". I totally expected her to be shocked or outraged, not agreeing.

Then the other official tells us about THE SECRET ENVELOPE. The lady opens a folder and shows us a white A4 envelope, she says "I have instructions to open this secret envelope at 6pm. It tells us who number 1 and number 2 are. If someone else actually wins, we ignore that result and just use the result from the envelope".

I left, completely shocked. The election really is rigged.