Even if you don't consume any carbohydrates, your body will produce some to continue its processes. So it will step on someone's toes only if they're science ignorant.

EDIT: Carbohydrates are used throughout your body. One example: as receptors on your cell membranes. The guff about "ketones are not carbs" below is a great example of how, "it will step on someone's toes only if they're science ignorant."