Conventional observation by restaurant staff isn't bundled and resold by data brokers. I find it astonishing that a reader of HN would be unaware of commercial data collection and resale practices.
Your credit card transaction is bundled and sold. Because it has value in establishing a consumer profile for marketing.
The fact that you visited some restaurant PDF or webpage from a dynamic IP address is not.
Like the parent commenter said, any information about how long the table is being occupied comes from the POS and reservation system. But that data is for the restaurant -- there's no market in selling it, though it absolutely has value to the restaurant for its business decisions. But your phone isn't being used for that part.
Data collection is certainly a thing. But it happens in specific ways for specific purposes.
Using a credit card tied to your identity, but then worrying about revealing your phone's IP address while ordering, doesn't make any sense.
No, it's you that don't seem to understand. I'm well aware that paying with your credit generates information which is repackaged and sold. But following a QR code to a webpage potentially opens your phone up to cookies, tracking pixels, and all sorts of other things, depending on what permissions you give it or what exploits can be leveraged. All the major fast food vendors have their own apps now, for example. One hopes they don't exfiltrate unrelated data from the phone, but it's not a certainty and it's even less of a certainty if individual restaurants start encouraging their customers to install a generic 'my tasty meal' app.
