Guy Betsy says: "they'll just endorse you to any carrier that'll get you quicker to wherever you want to go"

It would be good to hear more experiences on that regard - at least one poster (who may have been on award travel) mentioned that some intense negotiation was needed to get him on an alternate carrier, and others have said they were flatly refused non OW alternates. So what is the real story? Up to the pax's arguing skills, and the CX agent's willingness/power to authorize? Are they treating subclasses (F, A, etc) differently? Do you have to go nose to nose or are they trying hard to please? Does it depend what station you're at?