Just remember that deleting a folder does not delete its content! Files in google drive appear to be in folders, but this is really only at the UI level. Internally files are all identified by unique ids. When you delete a folder you are just removing your easy path to access the files within. They will become 'Orphaned Files' which are still accessible to collaborators and still findable in the search bar. The search command is:unorganized owner:me
will list all your orphaned files.
I am still trying to find a way to delete a folder and all its contents, short of starting at the branch tip ends of the folder tree and working back!