While not with CX, in New Zealand I have seen people refused a boarding pass because of no outward ticket from Australia.

One of these was a 20 something German woman (with a backpack) who ended up buying a ticket from Oz after much discussion with an airline staff member, who was busy tapping away on the keyboard as the argument continued. She handed across a credit card. I was next in line at the service desk.

In another case a small group of Asian gentlemen did not travel.

Is a risk without a ticket out.