The Royal toddler and his mum have spent many days out at Bucklebury Farm, near Reading, Berkshire, which is close to Duchess's parents' home, Bucklebury Manor.
But, according to The Sun, signs have been put up banning visitors from taking 'unauthorised photographs ... of other guests'.
However, residents in the nearby village think the move is an over-reaction by the farm's management.
One local told the newspaper: "Every photo we take there, even of our own children, could unwittingly capture other people and their kids.
"I took my daughter there the other day and saw Kate's mother with George and his nanny. I thought about taking a photo and decided not to.
"But protection officers still came over to us and challenged us. They were quite difficult about it."
Set in 77 acres of Berkshire countryside, Bucklebury Farm Park offers deer watching, nature walks, indoor play and tractor rides, as well as the petting zoo.
The surrounding area has been subject of tight security, as one family found out when their car broke down on the way to a day out at Bucklebury Farm.
Adam De Marco, 40, his partner Claire Lennon, 39, and their daughter Mia, seven, were on a family day out in Bucklebury, near Newbury, Berkshire, when their BMW's tyre punctured.
Their broken down vehicle quickly attracted the attention of royal minders, who ordered them out of the car.
But the security men put away their guns when they realised what had happened.
The family say they later spotted Kate, her mother Carole Middleton and Prince George at the nearby farm.
Carole has apparently helped to take charge of her daughter's recovery from severe morning sickness and has been researching alternative sickness cures, such as herbal tea, on the internet.
Elizabeth Hartley Russell, whose family owns the Bucklebury Estate, told MailOnline the policy was a 'moral issue' to protect children's privacy and was brought in after the Leveson inquiry.
She said: "It's not been done to protect any individual - it's been done to protect the rights of children.
"We're a family farm park. We're not here for people to take pictures of other people and put them on Twitter and Facebook.
"We've had children of actors, TV presenters and politicians. All sorts of people have come to visit the farm over a period, as they have to other family attractions. We're not alone in this.
"It's been a long-standing policy that we've had, and it's something we feel very strongly about."
She added: "Like any operator of a family visitor attraction, we are acutely conscious of the rights of the child – any child – to enjoy the freedom and privacy afforded by family days out at venues such as ours.
"The joy of special family moments such as these must be something that all parents and carers identify with and cherish."
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