Does anyone know if the new UA frowns upon duplicate segments, in two different classes of service? Scenario: I have a Y to C upgrade that's unlikely to clear, but I could book a free F seat on the same flight... I'm aware that checking in might be tricky but it may just work, too. The old UA was running a watchdog to detect and cancel duplicate segments, but the algorithm was rather limited and there were multiple ways to circumvent it. Any experience with the new UA?