Upon further thinking, I think what complicates all this is the fact that Gamestop recently purchased Impulse, another online steam-like store, so there's definitely a conflict of interest there, and what do you know.... the two versions of the game are their best sellers on Impulse right now. Now, we know that Gamestop is removing the coupons, and nobody's mentioned it, but could they possibly be putting in coupons for Impulse at the same time? That'd be truly devious.
Given that they were apparently unaware of the OnLive coupons, I doubt they had time to put together a strategy for Impulse at the same time. Though they will probably be thinking about it in the future, thanks to this debacle.