Hi,
I just went back to my OGS letter from a couple of years ago and it said that "scholarships are offered up to and including December 3". However, I was never notified (not once) either by phone or by mail that I would not be receiving an award or that I was removed from the reversion list. Once December 3rd came, I was never notified. I'm not sure if OGS has changed this policy or not, but in my experience, I wouldn't expect to be notified (unless you make it off the reversion list).
At the time, when I told the director/chair of my program that I was first on the reversion list, she said that I would likely get an award. She was one of the evaluators who sat on the selection panels. So, I think that my case was unique that year. I would encourage you to call OGS and find out where you are ranked. My letter stated "Separate reversion lists are maintained in rank order for each division of study." You will have a better idea of where you stand once you know your ranking. I think you are right, it also depends on your discipline.
Best of luck, keep is posted!