My concern with this look is that it's a "near miss". It doesn't make it clear that she is not conforming to the standard dress code for particular reasons. For example, wearing flats with a skirt is clearly the more comfortable choice, but it's not really the most professional look. But if you have a foot injury, wearing an orthopedic boot makes it clear why you're wearing flats -- hence, a pass on the flats.
@Sunbodi - Can you be more specific about what is and is not allowed? Is a head covering of some sort customary? And if you're willing, providing the name of your particular group might be very helpful.