As I wrote, I rarely use Sydney. Only (approx) 50% of my flights are Business Class (I'd have to check if that one was or not). That said, am not and never have been a fan of Sydney Airport at any time. Maybe I was just lucky in November 
I fly out of Brisbane much more often, and can confirm that ABTC card in Brisbane always gets the priority line for outbound security screening. In fact, I have only ever been asked why I am in the priority line maybe 20% of the time, I reply "APEC Card" and that's it. They seem quite happy with that answer. I don't recall ever actually been asked to prove it, by showing them the card or app.

I fly out of Brisbane much more often, and can confirm that ABTC card in Brisbane always gets the priority line for outbound security screening. In fact, I have only ever been asked why I am in the priority line maybe 20% of the time, I reply "APEC Card" and that's it. They seem quite happy with that answer. I don't recall ever actually been asked to prove it, by showing them the card or app.