Just returned from holiday in HK. Had a flight from MEL-SYD-HK for the outbound leg on 20 Dec, and came back 6 Jan on a direct flight from HK-MEL, booked as red e-deals in economy about 2 weeks before the trip commenced.
For both international legs, I got upgraded from economy to business, score! Both times, I found out I got upgraded at check-in. On the HK-MEL leg, they put me in business class on upper deck, first time I've gone upstairs, also pretty much everyone had two seats to themselves, ie. no one was sitting next to anyone, so that was quite nice.
Also, both times, my bags were one of the first out on the carousel, so that made it really quick transitions once I arrived at my destination.
I've been upgraded quite a few times on my domestic flights(fly from melb-syd and back once a week) as well, about one upgrade every 3 or 4 flights.
I have no evidence for this, or maybe I've just been lucky, but I reckon the frequency of my upgrades have something to do with the JASA's I flew last september to hit platinum. Not sure if that has somehow skewed me over into a "more valuable" segment or anything like that, but I've got friends who have been platinum a lot longer than I have(and have never flown business), and also flew to HK(on slightly different dates), and they didn't get upgraded. I seem to have been upgraded more times than my colleagues flying up to sydney as well, so not sure what the algorithm is they're using to select op-ups, but maybe I have managed to be segmented into a higher value group or smething.