Avoid Wearing Black
Members of the Royal family are instructed to avoid wearing black during the day. For Kate, black should only be worn during mourning and, on occasion, for nighttime events. To anticipate a funeral, members of the Royal family who are traveling to another country must carry a set of black clothes in their suitcase.
Then, if any family member dies, they have the chance to land in the UK properly dressed. The rule was stipulated because when George VI, the father of Queen Elizabeth II, died, she was on a journey through Africa, and when she arrived in England, she had no black clothes to wear when she got off the plane.