I'm not against this providing the print is sufficiently sturdy and they remain printed on some form of common ticket stock to provide a manual way to ascertain authenticity*, Belgian tickets look similar although there is some patterning on the front and the Aztec code appears to be done differently, but it's the same idea, I have taken semi-reasonable care of some and the ones I have had since summer still scan and read just fine.
Edit: Having said that, would some orange banding cost much if anything more at all to do? It is a key part of the branding that says 'This is a rail ticket, issued by the railway', after all.
*Why does there need to be a manual way to ascertain authenticity? In case a TOC hasn't kept its decryption keys up to date, something that has happened to me on more than one occasion and only 'let off' on the first instance because I was able to show the ticket in an official app. Before that, I was nearly accused of using a fake ticket (I'd originally shown the .pdf). I'd hate for the paper to be completely plain, I suspect if it were we'd get a lot of disputes and prosecutions cases arising out of just such situations.