This is related to internal bug 1135.

https://cvs.khronos.org/bugzilla/show_bug.cgi?id=1135

----last comment----
... the technique <constant> and <lambert> really define how the
goemetry reacts to direct lighting.  

This is separate from additional reflection layers and blending
transparency/refraction.

Rasterizer based viewer will typically not support this feature but raytracers
will.

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.
----