RIM had the same level of snafu recently as well with the whole BBX branding they went on about and then got told it was somebody elses.
Microsoft could just add another M infront and call it MMetro, but whatever they call it, it's putting a mobile phone interface onto a desktop, so what do they call it on there mobile platform?
ALso why did they pick Metro - what did it stand for Microsoft Enormous Tile Royalty Option(!) Meaningless Enviroment To Ride Obscurity(!) I don't know and I don't think they did either.
Still at least we have more faith in them testing thre software than we do there naming, don't we.