How can I determine if a node will be rendered?

Just wondered if there a method to tell whether or not a node will be rendered.  Camera.contains(BoundingVolume bound) would seem to work.  I was wondering if this test is already done during rendering((I'm assuming that method is used when the renderer does culling)), why can't I get the results of this test .  In fact is there a way to get a list of nodes scheduled for rendering?  I want a controller to stop executing if it isn't going to be rendered (maybe there is a better way to do this).

Appears that Spatial.frustumIntersects is updated on Spatial.onDraw.  Would looking at this field value be the appropriate way to enable/disable a controller?