It seems every time I go to check in, I have not received any of my requests ever. After asking nicely at check in, I've usually been changed to something close to my original request about 1/3 of the time. My requests aren't all that much: just bottom floor close to bus stop if staying in a Value or Moderate and top floor close to an elevator if staying in a Deluxe. I always book the category of room I want (savanna view, water view, preferred room, etc), so I'm never asking for an upgrade.