What I doubt is that it ever sees the light of the day. My reasoning is that everybody (right?) agrees threads should be a part of the standard. And yet we all have been witnessing how hard it has been for an agreement to be reached on exactly how to implement them. Well, GC adds to all the implementation issues, the fact not everybody thinks it should be part of the standard in the first place.
EDIT: Which actually leads me to one question... Is it possible for a program under C++ to implement its deallocation strategy with a combination of GC and RAII? That is, to choose the method on an allocation basis? Would this be desirable?