First of all, yes, restaurants would be a bit harder than typical. Second of all, I was thinking more along the lines of gas stations, where the QR codes can be

First of all, yes, restaurants would be a bit harder than typical. Second of all, I was thinking more along the lines of gas stations, where the QR codes can be applied in one visit and it could be as simple as having them fill out data and then redirecting them to the correct website. I doubt that gas station employees are regularly checking and ensuring the QR codes are accurate. And given the fairly muted, simple, design of many websites that require you to enter financial data, and the lack of information on what it should look like, then it would be relatively easy to create a website that mimics the correct website.