Originally Posted by WindFlyer

FYI Karen2, in terms of miles and elite boni, codesharing with US is the same as flying on UA. Where it is not is in the upgrades department, both redeeming, and earning (your flights on the codeshare do not count toward the 10k mile thresholds for e-500s), as covered in other threads.

Like you, albeit for different reasons, I was able to stand by for a flight on UA metal where I had been booked on the US codeshare. For anyone who wants to try it, I'd only recommend that you aren't yet checked in for the the US flight, otherwise you will have to go to US and have them "off-load" you from their flight so UA can re-book you on UA metal (sometimes an angel or un-hurried agent will call US for you and have them "off-load" you, but don't count on that).