I can't speak for China... but I have personal experience that Philippines, Lebanon and Kenya don't work either... If the mobile app is incapable of verifying it (OK, shouldn't be that hard), it would be good if the agent at checkin could verify it and its expiration and note it... then we could start checking in online for the return home... just drop bags (when needed) and go to the gate... Right now it ALWAYS requires talking to an agent...

And don't get me started on the inability to handle dual citizens, who hold more than one passport!