cameraTooHigh.cs

Vector3 currentCameraPosition = cam.transform.position - (this.transform.position + lookOffset);
Vector3 currentCameraPositionXZ = new Vector3(relativeCameraPosition.x, 0, relativeCameraPosition.z);
float currentCameraPitch = Mathf.Atan2(currentCameraPosition.y, currentCameraPositionXZ.magnitude) * Mathf.Rad2Deg;

if (currentCameraPitch > maxCameraPitch)
{
    // This camera is too damn high!
}