On the one occasion when I was invited to a Garden Party at Holyrood House, it was hosted by Prince Charles and Prince William. Neither wore kilts that day, although there were kilts in profusion among the guests, including myself in my Cunningham heavyweight kilt. The invite to a Royal Garden Party is intended to reach as many of the Monarch's subjects as possible and should you receive an invitation to a second Garden Party it is etiquette to politely decline and to point out that you have been to one already, in order that the invite can instead be extended to someone who has never attended.