Think of the trees. (of course manufacturing this extra piece of electronics is probably not "good" for the environment, but assuming that many people already h

Think of the trees. (of course manufacturing this extra piece of electronics is probably not "good" for the environment, but assuming that many people already have a smartphone, it makes sense to have a boarding pass QR code as opposed to getting everyone to print an A4 each time. Just think how many pages would be saved per year!)