For kicks and grins I poked around a bit (2012) and found a pair of vis that looks interesting...
My first thought was that it would be useful for situations where one dynamically launched vi creates a DVR and sends it to a second dynamically launched vi. When I put together a few quick tests to see play around with it I was surprised the DVR didn't automatically deallocate when the reference to the first vi was closed. (Nope, I don't dynamically call stuff very often.)
As I recall, we're told references are automatically deallocated when the vi that created it "goes idle." I've always interpreted "idle" as meaning the vi is not locked because another vi is running. So, either I'm wrong about what it means to go idle or the DVR already has the functionality of these prims built into it.
LeakReference.zip