You can always buy the upgrade certs for $50 bucks a pop for 500 milers. I think they still sell those dont they? Plus they do sell upgrades at the gate if they are available. Certainly not the best or most reliable option but an option nonetheless. I was gold preferred when US still had a limited upgrade based on segments. After loosing my status I was able to keep the upgrades and i was able to use them on flights at the gate after others had already upgraded so it does happen.