I respectfully disagree. OFFICIALLY she is not a member of the Royal Family, no matter where her place is in precedence or succession to the Throne. Now that the Queen, her loving grandmother allows her to use herself as Royal Patron, or represent her, well that is well within the Queen's rights to allow this. But the British Government & law courts look upon her as Miss Zara Philips, commoner.
Her mother, in 1973 specifically stated she wanted no royal titles or noble titles for her children, as she wanted them to grow up to be as normal as they could be. Much as TRH The Earl & Countess of Wessex have asked that their children not be HRH, even though OFFICIALLY they are.