Originally Posted by
eturowski
You can print your boarding passes to a PDF file and then send them to yourself, then just open them when the FA comes around with the beverage cart.
YMMV, though. In my experience, FAs are more likely to either look at the coupon and wave it away or just look at it dumbfounded and wonder what to do with it. I've never had one actually try to scan it or type in a number, which is nice, because then you can use it again.
I too print to PDF and show it on my phone. In the three times I've done this, twice the FA just looked at it and gave me my drink. On my flight on Friday night, he moaned a bit, but was able to scan the bar code.
Like others have said, probably no official policy and there is nothing in the fine print that says it has to be a paper copy.