If teachers feel a child is faking to avoid being in the classroom or taking tests, it's the counselor's job to work with the student to figure out what's going on, why the student is stressed and what to do to fix it.
The first to fall under scrutiny and question should be the teacher who has not the skills to engage children's natural curiosity and desire to learn and please! Next is the home life and social involvement and health/nutrition of the child.
Hungry, fearful, hurting, ill children have a difficult engaging in classroom learning as their engagement is just focused staying alive and warm another day. They need acknowledgement, security, safety, continuity, support, adequate food, adequate physical and dental care. Or concentrating on learning will be very tough.
Now adolescents are a completely different galaxy!