Windows RT can be hacked to run unsigned desktop apps, but Microsoft sees no reason to worry.
As described yesterday, the hack allows someone with a certain amount of savvy to change code in the Windows RT kernel so the tablet-based OS can run desktop apps. Officially, the only desktop programs that Windows RT supports are Microsoft's own Internet Explorer and Office suite. Otherwise, the OS can run only Windows Store apps.
But the hack isn't geared for the average Windows RT user.