Most of my double upgrades (from coach to first on UA 3 class 767/777/747-400) have come as a result of bizarre circumstances:
- Getting off a broken 777 (ORD-SFO) to the gate across where the 767 was full in business, thus they were nice enough to put me in first
- Mostly the reservation agents don't realize that I am on a 3 class aircraft and automatically give me 2A and the gate agent at check-in is too busy to verify. But i ain't complaining. I got my parents double upgraded SFO-JFK 2 weeks ago and they're not even Premier.

There have been all kinds of stories which I will share if we ever meet. As for the upgrades, I don't know if this is right, but I just wait for the agent to ask me for upgrades instead of just handing it to them.
Also, I tend to do the same flights week after week and have gotten to know the gate agents by first name. That always helps. Arming myself with a smile seems to work better than being armed with certs, right Catman?

As for the ORD-SFO. Getting upgraded on the 3:25pm 747-100 is difficult even as a 1K. I usually clear day of departure though. the 1:10pm 777 is a lot easier. other than that all the other flights are A-320's, 757 or DC-10's. Hope this helps

Double upgrades are illegal.Be careful about arguing with agent.they will put in your file,if you complain.Of course if the agent does it automatically it is her or his butt.

Vgrove, showing the smile and being NICE and
PATIENT has helped me get an occassional upgrade or extra perk in the past. I think I mentioned it before... we should always try to be nice.

It's the practical side of me that has to have the certificates and information at hand
as the co-back-up plan.

Luck can also help too!

As for double upgrades... I never thought they were possible. And I don't expect them.
If I can get into a comfortable seat that's my reward! CATMAN