Flying to Toronto this morning for an ISWG meeting, I used 'mobile check-in', in which a link to a QR code was emailed to my phone.
Of course, at Ottawa airport there is no infrastructure to read the code (and I so desparately wanted to swipe it somewhere) - I ended up instead showing the email to security and at the gate.
When I later tried to access the link from my laptop, I saw the following
Who made Air Canada the authority in charge of defining what is mobile and what is not?
My laptop is pretty mobile, but if I had tried to use it to show the QR code I would have been stuck.