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, my question is: How can I 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.
Someone mentioned a similar question in the comment. I find the answers/discussions there are not as engaging and fruitful as the ones I had here while the topic is the same. The author didn't even discuss any solutions he thought about in details. Yet, the question is not closed and mine is? What's the criteria for this?