Are You saying that the resources are not in use anywhere in the doc and Hype won’t let You remove them? I have not found this to be the case - they are always used somewhere in the project in my experience. When I remove all instances I have always been able to delete them from the “Resource” panel.
Also, if they are in fact not in use anywhere Hype does have something like this in the “Resources panel” at the bottom. Select the resource and then click the checkbox “Remove when no longer referenced”.
I still like the idea of the OP’s suggestion but a simple purge of unused resources can be done as shown above.
What is missing for me is when Hype tells me that the resource in question is in use (when I think I’ve removed them all) - where is this resource in use? Even if it was just ID’ing the Scene - on a large project (a large number of Scenes) this would be quite a time saver.