In fact you are correct: Negative examples, as in examples outside the higher-order class, are not used in the teaching of sub-classes of a "higher-order noun". However, in discriminating between sub-classes, examples of other sub-classes serve as negatives for the sub-class you are currently teaching.

Please see chapter 11 in TOI, "Hierarchical Class Programs", p 123.

We do care that they learn the terminology. When I said they are not accessible through 'simple' verbal rules like: "Listen: a bird is a small feathered flapping winged thing," I mean not that they are deaf or completely without language that you can expand, but that they are very young children (or older children from disadvantaged backgrounds, and I can give you a real horror story from my school demonstrating how little some of these families interact with their children, see end of comment) who would mostly not process and retain even such 'simple'-seeming rules like that.

Learners who are not yet familiar with the generalized concept of 'higher-order nouns', and must be shown that the way in which the verbal structure is the same for the statements "this truck is red" and "this truck is a vehicle" and the false statement "this truck is a dog" does not mean that you could find a truck that was not a vehicle in the same way that you could find a truck that's not red, or respond to the statement "this truck is a vehicle" with "no it's not! It's a truck".

A sequence for teaching the higher-order classes would start with examples of vehicles (sub-classes you are later going to teach) and differences that are as minimally different as possible (avoiding boundaries that are unclear even in the language of knowledgeable adults).

The wording of the first, modeled examples in the sequence could be like, "This is a vehicle/this is not a vehicle". The test example wording could be, "Tell me, vehicle or not-vehicle?"

Once firm, you move on to the sequence for teaching the first sub-class.

These are vehicles:

+This vehicle is a truck

[large difference to show sameness, a general principle derived directly from the basic axioms of the stimulus-locus analysis]

+This vehicle is a truck

[minimum difference to show difference (again, a general principle), using one of the sub-classes you will teach later as a negative]

-This vehicle is not a truck

Model perhaps a couple more, then

Your turn. Tell me if each vehicle is a truck or not a truck.

+Tell me about this vehicle "A truck"

-Tell me about this vehicle "Not a truck"

etc

Then in the next sequence you introduce a very different sub-class, like "boat"

+My turn. What kind of vehicle is this? A boat.

[big difference to the next positive to show sameness]

+My turn. What kind of vehicle is this? A boat.

+Your turn. What kind of vehicle is this? "A boat"

-Your turn. What kind of vehicle is this? "A truck"

etc

Continue introducing sub-classes as each becomes firm, juxtaposing members of the previously taught sub-classes with the new addition for discrimination.

Horror story: Once someone brought home the wrong kid, X, told them to watch TV, and didn't notice that it was the wrong kid until hours later when the school finally found the free time around their frantic search for the assumed kidnapper of X (actually just the person who had come to pick up Y), and phoned Y's family to ask why they hadn't picked up Y yet.