QR order - how to prevent customers from placing an order when they're not on premise

Question

From my understanding, a QR code is just a static link which get opened up when I scan the code with my phone's camera.

Once opened, a customer can keep the browser tab even after he leaves the restaurant. If that's the case, I'm wondering how I can prevent a naughty customer from refreshing the page and placing an order when he's not physically at the restaurant.

One possible solution is to force the customer to pay online immediately everytime he submits an order. However, this solution doesn't work in countries where cash payment is still popular.

Another solution is to make the QR code work inside the restaurant WiFi network only. This solution makes it harder for customers to place an order which is not a good thing, especially if we have to serve older audience.

I tried to google this topic but all I found are links to QR ordering software. I wonder how people are solving this problem in those products. If you happen to know, I'd be very grateful if you could share it with me.

Answer 1

I'd make the site only accessible via the wifi in the restaurant

Answer 2

Post a keyword in the restaurant. During checkout, the patron must enter this keyword in a field to authenticate that they are physically present before submitting an order. Rotate the keyword routinely (make sure it always matches the expected value on the site) to make it difficult for people to order remotely once they leave. To avoid human error, you could even have a digital display that automatically updates the keyword on schedule.

You could even make the keywords fit with the theme of the restaurant so that it doesn't seem too out of place.