Multiple outlets report that the Princess of Wales has reinforced fashion etiquette expectations for the Royal Box at Wimbledon through guidance described as a “secret dress code.” The reporting frames Wimbledon as a part of the UK social calendar with specific style norms, where attendees aim to avoid missteps in clothing choices. The articles also attribute commentary on how such etiquette is difficult to master to Ceril Campbell, whose observations are presented as part of the Palace Confidential newsletter.

Overall, the coverage focuses on the existence of unspoken or less-publicized expectations surrounding attire and presentation in the Royal Box environment. It does not provide detailed, verifiable specifications within the shared excerpts, but emphasizes that Royal Box standards are influenced by tradition and context, and that dressing appropriately is a recurring concern for people attending the event. The articles position the Princess of Wales’ remarks as part of broader efforts to align public-facing appearances with established ceremony and expectations at Wimbledon.