I have no test case available for this, however I'm very certain of it.
I note that now I use my own switch system anyway, because removing the children from the scenegraph is far better for memory and performance than attempting to conditionally traverse the tree.
My personal thoughts on this:
Also I've found the links and sharedgroups are slow, and nearly the exact same benefits can be gained by simply sharing the Appearance, texture and coordinate buffers at the lowest level.
I recognize that shared groups are supposed to make sharing a complex scene graph sub tree easy, but given that ALL interesting sub trees are loaded from file, it's not a very useful mechanism (in my opinion).
Notwithstanding the above the links under switches MUST be made to work again.