Ok, real world example from two of my projects. I had two projects, with two different directory structures. They were different because the projects were started on different releases of the engine, when different capabilities were introduced. Both projects were upgraded to the latest engine version, which supports components. I had a component in one project that would work well with the other. I migrated the component over, which grabs all the dependencies including the folders that they reside in, and moves them over to the new project. Now I have several extra folders in my project, each containing only a single item that I had been keeping stored elsewhere. (structs/enums/etc) So, I move the files, save, close, open, fix up redirectors, and commit to svn. However, unreal had not deleted all of the directories/files, so it duplicated them in the SVN unbeknownst to me. On the next SVN update. It pulls down all the duplicated files, which of course breaks all the friggin references and forces you to repeat all those steps again, possibly with the same broken outcome.