Yes, they were afraid someone was going to leak it, and that someone was Executive editor Dan Wootton of the Sun. In the links I put up here (#246) Wootton states that he gave the Sussexes and the Royal Households a certain time to respond and he was then going to print with the story. He did go ahead and print. His source in fact had rung him about the Sussex’s departure when he was in NZ visiting his family, and he decided the source was viable.
Right. But that didn't mean that they had to put up that website and make the announcement right away in the fashion that they did. Which clearly was a shock to everyone else because they publicly went "we didn't agree to any of that!" And then the Summit where the Sussexes got very little of the Half in, half out that they wanted.
The website had clearly been worked on for some time, it looked professional even if the content was a flight of fancy.
Meghan also left Archie with Jessica Mulroney and stayed in the UK less than 72 hours, just long enough to go to Canada House - a move that BP didn't approve, and then fly back. That suggests a lot of planning and that the story would have leaked as soon as people realised she wasn't in the UK anyway.
I'm not saying they leaked it but there was a lot more potential for knowledge among the Sussex staffers, the people in LA and friends than the other groups who were clearly caught unawares by the Sussex Royal website and manifesto.
However secretive they may have been there were too many people involved to be sure that someone hadn't told a PA in Meghan's US team for example. And as I said Tom Bradby was giving interviews saying he thought that they were going to leave and they can hardly blame that on BP or KP.
The best thing for the royal households would have been to agree a peaceful settlement with the Sussexes, anything else just made everyone's lives that much harder.
Harry and Meghan then made it much harder for *themselves* by releasing something that hadn't been agreed, in a very chaotic manner, clearly hoping to present some form of fait acompli to the media and hope the BRF would go along with it. And were shocked when they didn't apparently.