I truly believe that a mileage upgrade waitlist is usually ignored.. Our experience (much more often than not) has been Plat on waitlist for mileage upgrade is trumped at airport by early check-in Silver with no miles.. Haven't tried since T-3.0 EUA, so really don't know how it would bw handled now... Have also never had a waitlist automatically clear for mileage upgrades; have called in a few times when F appeared and had it processed, but never had it done automatically.. In the past year, we have never had a waitlist clear AT ALL, and therefore look for any flt where F is already open when we book...

Robin