That's cool that they have this guarantee....

But last year I had a 100% upgrade track record of flying NW. CO was about 75% and thank god, my company bought me Biz on DL because there are of course, no upgrades on DL for NW/CO elites. Alaska sucess rate was about 50% Upgrades using the NW Gold/Plat certificates.

In fact NW has already upgraded me for a Thursday flight. Way to go NW!