Originally Posted by
canadiancow
When I'm wrong, I'm wrong.
If there is no valid ticket at all, you cannot check in. But if there is a valid coupon for the first segment, but not the second, our old friend COUPON REQUIRED has come back under a new name. PAPER TKT.
So do not assume that completing checkin under 1A means you're good. Continue examining boarding passes.
Thanks for the heads up. That COUPON REQUIRED has given me (and concierges/staff) many headaches.