When I first started significant travel for work my first long project was in Quincy (should I type that "Quinzy" ) so I did a bunch of COU-ORD-BOS trips, and occasional COU-DFW-BOS. Once I hit Gold status I requested sticker upgrades every time. They cleared fairly regularly, which at the time I assumed was perfectly normal, but now looking back seems weird. I'd ballpark it at something like 20% success rate, which then climbed to maybe 40% when I got to PLT. I hadn't figured out the game yet so I ended that year (2015) still PLT and flew that status most of 2016, till I hit EXP in September. Not sure what it is about BOS, or whether we're just seeing noise in a small sample, but I definitely feel like I did better there than most other places when I was low status.