KML line positions not being clamped to terrain

This KML uses the clampToGround altitude mode and tessellate = false by default. The line positions should be clamped to terrain but the lines themselves should not (they should cut through the terrain). In Cesium the heights are set to zero so it clamps to the ellipsoid instead of terrain.

<?xml version="1.0" encoding="utf-8"?>
<kml xmlns="http://www.opengis.net/kml/2.2">
  <Document>
    <Folder>
      <Placemark>
        <LineString>
          <coordinates>-94.2853118971204,34.0604044149558,200.0
            -95.2849440296246,34.0600224952286,200.0</coordinates>
        </LineString>
      </Placemark>
    </Folder>
  </Document>
</kml>

Begin with the supplied KML example using clampToGround and tessellate=false, then trace the KML loading path that handles LineString positions and altitude modes. Compare the resulting line positions with terrain and ellipsoid heights; done means positions follow terrain while the line geometry still cuts through it.