The problem is that the check-in will be in Russia and the agent has perfect bribe material, with little incentive to expedite the check-in process until they have finished pointing out how impossible it is without the right incentives. Citing the rules in these situations causes a delay, perhaps sufficient to miss the flight (and then the award ticket becomes invalid, at least in Russia). Of course it may not play out like that, but this is a common scenario in my experience, and expedience is the better part of valor.