For example, she is not allowed to fly on a plane with both her husband and father-in-law — Prince Charles — at the same time.
Those in the line of succession cannot travel together by plane or boat to ensure there is someone to assume the crown in the event of a fatal accident.
Trendchaser has put together a long list of other things that Middleton is not allowed to do as a royal, and we have adapted that list below.
Scroll down to read more about the royal family dos and don'ts!
No Signing Autographs
While being a royal may seem like celebrity status, there are actually some limitations to the similarities. Such as not being able to sign autographs.
Per the rules of the crown, Middleton is only allowed to sign documents that have been previously approved by her grandmother-in-law, Queen Elizabeth II.
This reasoning for this particular rule is due to a concern that criminals could attempt to forge her signature.prevnext
She Can Not Earn Her Own Money
She may be a professional photographer but, per royal guidelines, Middleton is not allowed to profit from her work.
Rather, her photographs are released to the public by way of the palace.prevnext
The Queen Comes First
Technically, this particular rule applies to everyone in the royal family, but it is still an interesting "don't" nonetheless.
While having a meal with the queen, once she finishes eating everyone else at the table must put down their utensils and stop eating as well, even if they are not finished eating.prevnext
Mussels and Oysters Are A No-No
In one of the more unusual rules, Middleton is not allowed to have mussels or oysters for any meal.
This particular rule is in place because these particular seafood items require very specific storage and preparation, otherwise they can lead to health hazards that royals cannot risk.prevnext
Nail Color Policy
One would probably not think of something as inconsequential as fingernail polish being a big deal but for the royal family it is.
According to Royal protocol, Middleton has only two options when it comes to nail polish color — Soft Pink 28 Rose Lounge (Bourjois) and Nude 423 Allure (Essie) — as she expected to maintain a natural look.
Interestingly, Queen Elizabeth has been using the same nail polish for nearly 30 years.prevnext
No Personal Social Media Accounts
This rule may seem a bit excessive, but the logic behind it is somewhat sound.
Middleton — and all members of the royal family — is not allowed to have personal social medai accounts in an effort to avoid identity theft and a leak of private information.
The royal family does have official social media accounts, but they are managed by palace personnel.prevnext
No Public Displays of Affection
While it is probably tough for a loving couple, Middleton and her husband Prince William are not allowed to make any public displays of affection.
This is said to be due to the Queen finding it to be unbecoming of royalty.prevnext
Strict Dress Code Policy
Members of the royal family are required to follow a very strict dress code when it comes to what they appear in while making public appearances.
Middleton is not allowed to wear leather that comes from a sacrificed animal, nor is she allowed to wear clothing with bright, vibrate colors.
Additionally, there are very strict rules on when the Dutchess can wear black. The only times this color is acceptable is for evening events and funerals/mourning periods.prevnext
She Can Not Vote
When she wed Prince William, Middleton gave up her right to vote, in a manner of speaking.
Royal family members are forbidden to vote by rule of the Queen so they remain neutral on Parliament issues, but they are not prohibited by law.prevnext
No Monopoly Allowed2comments
By far the most surprising instruction in the whole Royal family rulebook, no one is allowed to play the board game Monopoly.
The rule came about not that long ago, as in 2008 the Duke of York — Middelton's uncle-in-law Prince Andrew — issued a decree defining it as a "vicious" pastime and inviting all of the Queen's subordinates to abstain from playing it.prev