@Gettinagoldtoof
I live in central London, huge numbers of businesses are going cashless. I always complain and usually leave.
I doubt the counter assistants are bothered nor will even report up to management. The owners/managers will have made an informed decision and will accept/expect a certain level of customer refusals.
Whether we like it or not, it's happening. At my son's Uni, literally everything is cash free. You can't even buy a coffee with cash as the catering outlets (for both students and general public) are card only, as are the campus shops. It was his graduation last week - photos, souvenir stands, etc all cash free. If you want to print or photocopy anything you have to "top up" your student account and enter your student number into the machine - again, no "cash" option. Same with the campus laundries. In the 3 years he was there, he says he literally never used any cash - he brought back the few notes we gave him when we took him - untouched!
At most football matches we go to, they're cash free. You have to use your card to buy a drink, pie or a pint. Our home ground has been like that for a couple of years, and more and more away grounds have changed now.
More and more buses are going cash free and require payment by card or tickets bought in advance on their apps. No need for a mobile signal in rural areas as the card machines are set up to take details of your card, memorise and process later when they get a signal. Same happened on a heritage train ride we took over the Settle and Carlisle line - bought some coffees when the train was in the middle of nowhere - no mobile signal, but the cardholder accepted payment anyway. Not having a signal doesn't stop a vendor taking card payment in places where there isn't a signal - they just need a different kind of reader/merchant account that provides for it! Same with car park machines - likewise they can read the card anyway and just charge/process it later.
The younger generation are virtually cash free already, and as they grow older, future generations will likely be coming through cash free. It's far too late to reverse it.