But isn't there a distinct disadvantage to being absent from the EUA list and relying solely on the "battlefield" (ugh, I hate that term) upgrade? This same thing happens to me when the first flight is on UA and I am connecting to CO - you can't check in on CO - you won't even get the option to do so. I always do check in with UA first, but that doesn't seem to trigger anything perceptible in terms of your place in the upgrade queue.