Very interesting. I have been QR Plat for over 5 years and have only had one upgrade in over 100 sectors flown, the only one being on a short KTM-DOH leg, though luckily while flying with my father. I have had several upgrades on other OW airlines though (CX, AY, MH) in far fewer sectors owing to my OWE status, which again is interesting considering that your "home" airline is presumably supposed to take care of you the best. On the flip side, I know of cases where friends/acquaintances with no status or Silver being upgraded routinely, even on sectors that are traditionally known not to have overbooked Y. So I suppose there is no method to this madness.