Depends on how you define "fair," and the same argument can be made of exhibitors and other specialty groups - with the added wrinkle that you would also need to determine how many events would qualify someone, etc. Some of those have their own hotel block, some don't.
And there's the further complication that we don't know who GMs are yet, since event submission is still ongoing, and we need to complete event review and placement before we know what final schedules will be like. We can't easily move housing registration to after that or move event placement before housing, so scheduling simply doesn't make it viable.
For GMs, we do have a dedicated housing block, but it's intended for use as a fall-back if you aren't able to secure other housing, basically, and for complimentary rooms so that a gaming group doesn't need to shoulder the up-front costs of their rooms.
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