Yes! This was the experience I had with Australians. They brought a cool box of booze to a bbq and at the end of the day packed up any of their undrunk alcohol (inc. half drunk bottles of wine) and trotted off home. That's why I suspected it was a thing in Australia.
I can help you with this
. We have different ‘rules’ for different occasions.
If it’s a dinner party, you would not bring an esky. You would bring a bottle of wine, maybe a soft drink, chocolates or flowers. You most certainly don’t take anything away with you. That would be weird as fuck.
BBQ’s are completely different due to number of attendee’s, and obvious issue of host having finite fridge space. There is no way they can fit everyone’s beer/wine in the fridge. There will be a LOT more alcohol consumed at a BBQ than a dinner party, and whereas at a dinner party red wine (no refrigeration) may be popular it’s extremely rare at a BBQ, rose maybe but not red. Essentially, the host would virtually need to empty out the entire fridge, no food could go in (not healthy as chicken/seafood features heavily and you really want it refrigerated), and even then you’d be lucky to fit everyone’s booze in. We drink ice cold (particularly beer) so putting some in when some taken out will not work, not enough time for it to really chill before that comes round out. So, typically everyone, including host, has an esky, to leave the fridge free for meats/salads/dips/desserts.
If you are going for a BBQ and it’s just your family and host family, you would not take an esky if only drinking wine, but probably would if drinking beer - again, fridge issue. If not taking an esky and just a couple of bottles of wine, you would never take them back. The rule is you don’t take anything back out of someone’s fridge, or if you have not taken an esky, just not done.
With an esky, you just take what’s in it home at the end. The alternative is getting out dripping wet bottles of champers/wine/beer (as ice will have melted by end or be a big slushie). You’d need to unstack esky and leave it in a big puddle and say to hosts ‘good luck with that lot’. No one wants to bring dripping wet drinks in, and dry each one to store
. I don’t understand the person who said Australians get the leftover booze at the end of the night and put back in the esky. It stays in the esky. You would get an individual bottle of beer out to drink, or a bottle of wine out and offer it around and if any left over (never happens), put it back in esky or it will get warm quickly and then no one will want it, someone else would get a cold one from their esky instead.
A few decades ago the problem was moot in that every host filled the bathtub with ice and everyone dumped their drinks in on arriving and left whatever was there on leaving. However, back then every toilet was seperate to bathroom so no issue everyone going in/out to get drinks. Now, houses have been redesigned/renovated to give an extra toilet in the bathroom as well, which makes using the bathroom problematic so at that point we all (as a nation swapped to esky’s).
That’s the Australian booze etiquette lesson for today 
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