I've seen the "overzealous barcode scanner" issue happen with some gas station POS systems, to the point where the seasoned cashiers know to cover the QR codes with their fingers before attempting to scan an item.
The modern reader firmware tend to have multiple modes and many options. Some modes are as simple as "scan whatever you see out of the many formats you support, and spit out the decoded value of something as USB Serial". Or, worse, "...as USB Keyboard".
You can imagine how easy those modes are to integrate with POS software, without implementing the proprietary protocol for that device, and you can also imagine how poorly that can work out.
If you owned a store with a POS setup with flaky reader behavior like this, and were stuck with it, you could try reconfiguring the reader (to, say, disable QR support). This reprogramming can sometimes be done via documented protocol, via sketchy Windows software, or via... barcode... Careful you don't make it worse.
(Our startup used modern readers (multiple 1D formats, QR, NFC) for a factory station, and had to do a lot of experimenting with different brands and models, to get the behavior and speed we needed. We even managed to brick a reader, just with configuration changes, not flashing firmware.)
That was the main theme of the book. Everything was well designed with failsafes, but too many of the design assumptions turned out to be wrong. Expecting only the expected lead to many small mistakes that were harmless individually but together snowball into a disaster.
(Well, not obviously dystopian, more ‘oh shit, that is how we’d be fucked isn’t it). Alien and Aliens also had a similar feel in their writing, except in real life there is rarely a Ripley there when you need one.
Kroger, for example, has an app that allows you to scan items to add them to a virtual cart as you shop and avoid scanning them at the register... however the same app is used to read QR codes on in-store coupons, which are "helpfully" placed very close to the price tags with UPC barcodes on them.
If I want to scan one of those coupon QR codes, I need to either start with the camera very close to the QR code or cover the barcode with my finger.