NES Emulator Nixed On Xbox After Passing Certification

So yesterday "NESbox" made all the gaming sites as an NES emulator that managed to get green-lit for sale on the Xbox store. Not too long after, Microsoft realized their goof and pulled the app from the store. Their reason, surprisingly, was not that it played Nintendo games. 

Instead, Microsoft stated the app was pulled as it wasn't uploaded via the ID@Xbox program. Granted, that news comes from Reddit, but seems to be confirmed by other reports. 

Does this mean that Microsoft will actually allow an NES Emulator to be downloadable on their platform? I can't imagine how that will go with Nintendo, but then again I don't know how the legality of all that works. 

Part of me wishes they do it and both consoles go to war offering their products on their respective consoles!