Kiwiland
We've had something similar for a while (covid app with QR codes at businesses. Scan code, adds an entry to your diary stored locally).
During Lockdown Season 2, it became compulsory for businesses to display a code (our health ministry website has a tool for generating the code, which you can then print off). Some businesses took it a step further - display a code and a manual sign in sheet: Please do one or other or GTFO.
As for supermarkets and other areas with lots of patrons: displaying multiple codes helps. Also, as a nation, generally we have gotten pretty good at scanning: as you approach, you get your phone out, launch the app, start pointing it at the sign. I'm had it register from about 2-3m away.
Biting the hand that feeds IT
