Unfortunately, airlines in this country make you sign a waiver basically saying that they won't have to buy it if they break it. They refuse to carry it if this waiver isn't signed.
Don't fly Qantas.
I wouldn't even purchase a ticket with an airline that had such a ridiculous waiver. I can't imagine them taking care of your bike after you sign a waiver saying you won't hold them responsible because they're a bunch of boneheads and throw your bike all over the tarmac.