Last week the electricity went off in the newspaper office where I work. A lady came in to renew her subscription. She had her renewal card with her, and was writing a check, so there was no problem, it could be rung up when the electricity came back on.
The young lady at the counter actually told her that she could not give her a receipt because the electricity was off. Of course we have printed receipt forms, which we used for many years until we got the new cash register that prints a receipt a few years ago. I handed her a receipt pad, and she looked at me like she thought I'd lost my mind.