Students sometimes send screenshots or photos of the results page, and it would be nice to be able to verify the receipt shown. It's a hugely long string, so typing it in isn't feasible. A QR code could encode that information, but in order to be usable it has to be quite big.
To be really useful, the QR code would contain the URL of a page that verifies the receipt, instead of just the receipt.
So, I think the options are:
always show a massive QR code, taking up half the screen. The student would have to try hard to mess this up, but it would annoy people who just want to see their results. If it can be dismissed, then students could easily do that before taking their screenshot.
show a button to show the QR code. But could this just be a link to the validation page, and skip the QR code? I suppose some students find it hard to copy out a link into an email, but could easily take a photo of their screen.
Students sometimes send screenshots or photos of the results page, and it would be nice to be able to verify the receipt shown. It's a hugely long string, so typing it in isn't feasible. A QR code could encode that information, but in order to be usable it has to be quite big.
To be really useful, the QR code would contain the URL of a page that verifies the receipt, instead of just the receipt.
So, I think the options are: