Last year I had a self-printed boarding card and was told by the checkin agent that it wouldn’t work. I declined for her to print me a “real” one. She then turned her attention to my wife and told her that there was no way I would be getting through. “You’ll be back here in 10 minutes!” …. as we walked away, she called my wife back over and ‘slipped her’ a boarding card for me.

Of course my printed one worked just fine.