When I've used online checkin I almost always get my room early, either when I check in, or before noon......However, whenever I've done online check in, esp. at BWV, I NEVER get any of my request.
So in May, the online checkin was not working, so I couldn't do it for my BWV stay and surprise, I got all of my request!
I guess it's all in what's the most important, the hopes of getting a room early, or getting any of your request.
I no longer use online checkin now. It's nice getting your room early, but I would rather have my request fulfilled, or at least the possibility of having them fulfilled.
This is just my observation, however, so not official study on the results. I have used the online checkin at least 6-8 times prior to my May trip.