Any POS terminal should be able to work with power only. There’s probably a dusty manual somewhere telling you how to configure it for the store to enable it and allow the cashier to type in an amount owing and then hand to the customer and queue payments for upload when network connectivity comes back.

Might lose some payments to overdrafts or cancelled cards. But they lived with that with credit cards up until 2000ish.

Buy-on-board on Aircraft and trains take advantage of this.

Offline payments is baked into EMV payments. It can at least verify the PIN and that the card was valid at its last phone-home.

https://www.google.com/search?q=mastercard+emv+offline+payme...

with pen and paper books can be kept

But you cannot pay with a pen at a cash registry

You can't, I can at certain registries in my town.

It’s a co-op store. They know who you are.

It’s a co-op by name only. These days, Coop’s just a regular supermarket.

This should be illegal.

Coop the store chain is owned by a cooperative association (https://en.wikipedia.org/wiki/Kooperativa_F%C3%B6rbundet) so would say it is legit still.

Why on earth should a member-owned structure be limited to some little store where everyone knows everyone? In the US some fairly large organizations, including juice makers Ocean Spray and outdoor chain REI, are co-ops.

Just because the organization is a co-op (of co-ops in the case of the overall parent org) doesn't mean it knows all members of the public that go shopping there.

It doesn't mean they socially know everyone that shows up, but every member would have paid some amount to buy (a) share(s), at least that's how coops work where I am. Plus accumulated dividends. That's a relative barrier to fraud if they decided to issue credit to members.

You could still fraud hit them in this circumstance, but they have some kind of info printed on your card with your name on it and how long you've been a member, and somewhere in the background, a phone# and address.

If one wanted to commit retail crime, easier to just take stuff and walk out without paying.

They are not limited to members of a participating co-op. Everyone can go shopping there.