Posted 13 February 2013 - 02:30
I think Microsoft has made it clear to software developers that creating Modern Windows Store (formerly Metro design language) apps that make use of the Win32 API framework will result in the app getting pulled from the Windows Store (assuming it managed to get listed in the first place). In extreme cases, I suppose the developer might lose access to the store, entirely. I would imagine that any attempt to use any kind of native code for the ARM CPU would result in a similar action.
The only narrow exception I can think of would be for a hardware manufacturer who wanted to provide a Modern Windows Store app that managed some hardware, like toggling the backlight on the keyboard or something similar. If something like that were to occur (and, again, I'm only speculating) I would imagine the program would have to go through a far lengthier review process with a lot more scrutiny to ensure it doesn't cause any instability, performance issues, contain any vulnerabilities and so forth.