I'm very surprised there's no prior art here. It seems like something I've seen before, although I can't think of any specific examples. (I've definitely seen old flashlights designed for those big square 6V lantern batteries so that, as long as you put the thing in with the contacts facing up, they would always work...)

If there's no prior art in the wild, then my tendency is to wonder why not -- I find it pretty hard to believe the guys at Microsoft are the first to think of this. I wonder if some poorly-manufactured batteries would short out the contacts, and that's why other designers have shied away from doing it?