For some drag and drop apps (bookmarks toolbar, window, etc) it would be nice to know when a drag that ends outside the app in the trash, so operations like Delete could be used. (In this example case, you might delete from the bookmarks ds and create an internet shortcut file in the trash so that the user could drag it back in later if they change their mind)
pinkiemon & component change
i have been thinking about this a lot and would like to do it.
For reference, here's a URL to a snippet of Apple code for detecting when a drag ends in the trash: http://developer.apple.com/carbon/tipsandtricks.html#DragTrash