This is related to internal bug 1135.
... the technique <constant> and <lambert> really define how the
goemetry reacts to direct lighting.
This is separate from additional reflection layers and blending
Rasterizer based viewer will typically not support this feature but raytracers
In 1.5 we could move it out to a higher level but current consensus was to
leave it as to maximize backward compatibility .... "if it ain't broken..."
This is open to a revisit.