@Doug *******
Why would they need to look at it? Either it shows up in their system automatically or they will ask for the QR code or confirmation code.
They might ask for these if you're entering shortly after having filled out the form and it hasn't made it to their system yet.
It may also be border specific; the first time I did it, was in the morning and I re-entered Thailand that afternoon, no need to present anything but it was a big border crossing.
Second time, I did it in the morning and re-entered Thailand by car 2-2.5 hours later. The officers wanted my QR code or confirmation. I took a photo with my phone (just in case) and that was good enough.
On the first trip, I don't think I took a photo of anything but would have had confirmation in my email.