Once Prince Harry left his native England for the U.S., he lost the protective insulation of being a member of the royal family. In Vegas, he agreed to participate in a private game of strip billiards. The photos from TMZ show that he didn't make out so well. In addition, he dallied with a nude female.
Those photos can damage the reputation of the House of Windsor aka The Firm at a time when much of England is experiencing soul-numbing austerity. It's not impossible that head of The Firm Queen Elizabeth II could find herself out of a job.
The ethics and legalities of privacy are not restricted to what occurs or doesn't occur on social media networks. In a private game, what are the expectations for confidentiality? Will The Firm's barristers be consulting with America lawyers about what harm might have been done and what remedy would be appropriate?