Dragging a folder into the keywords UI

I would love to be able to drag a folder into the Keywords pane and have it automatically populate the Keywords UI with the title of the folder as a category and the sub-document titles as the kewords in the category (possibly even recursively if the folder contains other folders)

So like:

Characters (folder)

  • Eli (document)
  • Bart (document)
  • Tentative Characters (folder)
    — Mary (document)

Drag characters into the keyword pane and it reproduces that tree with folders as categories and documents as keywords.

I think that would be useful.