Good on you for leaving! Most people would have just caved and handed over plastic. It is a worrying situation but I think in Australia this will probably become more prevalent than in other parts of the world. I guarantee you that here in South Africa if they tried to ban cash, there would be a massive growth of black market dealers who WILL accept cash. When the lockdown started here in March, the "government" tried to ban cigarettes, buying t-shirts and open toed shoes (communism much?).
Well we the people later found out that the minister of health has an interesting friendship with a mafia black market cigarette dealer (among other things), so the illegal sale and purchase of tobacco went nuts. You create a vacuum, someone will find a way to fill it - guaranteed.
We actually had the opposite happen to us a few days ago. Since we moved here we've been trying to support more of the smaller, family owned businesses. We found a little dairy and they ONLY accept cash 😏 my kinda place!
I'd also give that shop that refused your legal tender a below average rating for that somewhere online, but that's because I'm a bit of a cow when it comes to stuff like this.
You make an interesting point about the black market there and it makes a lot of sense. Everyone is out to get ahead I guess. It's less of a thing here though and so I think it's more about trying to prevent staff-theft, record keeping and covid fear. That last seems laughable though. Of course, the government love card payment as they can track everything through the bank feeds. Banks here require our Tax File Numbers to open accounts.
Quite a few places have card only signs, as did this place I went to, some very big national retailers too...I tend to avoid them. It would have been easy to pay with my debit card and walk away but I decided to do an experiment. She stuck to her guns and so did I. 🙄