>required to present a QR code on your device I so hate this. I have repeatedly seen PDFs containing nothing but a QR code and text like "not valid if printed"

>required to present a QR code on your device I so hate this. I have repeatedly seen PDFs containing nothing but a QR code and text like "not valid if printed" - this is truly silly. QR codes were created to form a bridge between the physical and the digital world, exactly so people can print them out. If you want it to be digital-only for some reason, use NFC or Bluetooth or whatever.