1. They Have To Travel With Black Outfits
When traveling abroad, every royal member must pack an all-black outfit in their suitcase in case of an unexpected death. This became a rule when King George VI died, and Queen Elizabeth II rushed back to England on a plane from Kenya. She couldn't disembark until she had a mourning outfit on, and had to wait in the plane for hours until it could be fetched. In order to never encounter that problem again, the rule was established. That means the royal kids always have black outfits packed when they leave the palace.