I can't answer your question directly but I wanted to seek clarification.

There aren't any non-stops from Calgary to Australia, so I assume she's flying to an intermediate transit airport first.

If that transit airport is in Canada, she'll need to visit that duty free, not the one in Calgary, i.e. if she's flying YYC -> YVR -> SYD she'll need to visit the duty free in Vancouver.

If she's transiting via the USA she'll be able to visit duty-free, but will need to adhere to the US import regs, not the Australian regs (they may be the same, not sure).