Richard Fitzwilliams contrasted the move to Prince William's more open approach with school children in New York City last week.
The Prince of Wales harvested oysters in the East River last week, and students from the Harbor School helped him clean the used shells.
The young children spoke positively about the experience to the media, with one student telling Hello!: "It was pretty incredible. He was genuinely interested in all our work.
"This work is really important to all of us because we all live in New York City, this is our home."
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This is a sharp contrast to William's younger brother Harry, who visited Public School 123 in New York with the Duchess of Sussex in 2021, and reportedly insisted on the school signing an agreement which would ban anyone commenting on them in a negative light.
Sources told The Sun that a standard agreement was issued to the school. It remains unclear if the terms were ever finalised or dropped.
In an exclusive interview with GB News, Fitzwilliams compared the Sussexes' "weird" attempts to control the narrative with the Prince of Wales's more relaxed approach.
He said: "It's very peculiar, it's extraordinary because I mean this is taking privacy to extraordinary lengths. Firstly, if you're looking for favourable publicity, and the Sussexes love both publicity and favourable publicity, you wouldn't do this sort of thing.
Meghan and Harry's decision branded 'weird' by royal commentator
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Prince William harvested oysters with schoolchildren
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"Secondly, usually they're very presentable in crowds, always say with children. The whole idea of doing something like that is weird because it's totally counterproductive if it gets out, as it has done.
"But also, it's impossible to know precisely what the children could have said that wasn't favourable."
The royal expert claimed that Meghan and Harry could have been "cold", which could explain why they instituted the gag order.
But Fitzwilliams maintains that it was a "weird decision" from the Archewell team: "The Sussexes could be cold, putting it mildly.
Children spoke positively about Prince William to the media
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"They're royals but they're also very significant celebrities, if you look at it like that.
"This is a weird decision by their team, it must be. Because otherwise, you couldn't go and mix with children and expect children not to like you.
"It's inconceivable that they would have thought that the children would say anything negative.
"The whole purpose of appearing with the children would be generally positivity.
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Meghan and Harry received 'weird advice' from their team according to the royal commentator
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"It's bewildering but it's hard to imagine Harry and Megan themselves sitting down and making this decision.
"I think, sometimes they do get very, very weird advice. `That is the only thing I could possibly say because obviously, it's just extraordinary, but it's obviously counterproductive now it's got out."
When asked if Prince William made the right decision to allow the Harbor School students to speak to the media about their experiences with the royal, Fitzwilliams said: "Well obviously.
"It's very very weird advice that they've received, it's hard to imagine Harry and Meghan planning this sort of thing. It's a very weird decision.”
