I don't mean flat-out deny, There's a reason why simple social engineering works with a very high degree of success, and manipulating small children who have trust in his kidnapper (which isn't rare, since they're often family members) is even easier.
While we perhaps inculcate a bit more compliance than is strictly necessary, you can't make children not gullible. To be not gullible irreducibly requires enough experience with what is normal to know when something is not normal, and alas, not only do children have a straight-up calendar disadvantage there, the children that we are talking about are also more likely to not have a normal to compare against in the first place.
> Which is why I suggested raising less gullible, passive, compliant people. Gullibility is a problem, here and elsewhere.
Young children are going to be gullible and compliant because they are young children.
That isn't something you can change until they are no longer young children. It's a question of both the teaching time required and the mental development required to learn those skills.
Similarly, some older children and adults are going to be gullible and compliant because they are mentally handicapped. Again, this isn't something you can fix by training them.