And from what I remember, Princess Anne was determined to give her kids as "normal" an upbringing as possible (however normal you can be, being the offspring of royalty) - her kids don't go by any titles and, apart from occassional sightings on the royal balcony, aren't involved in the family "business". So if they are behaving, for the most part, as commoners, why can't they sell their story to a publication the same way a commoner would.