Ever move/delete music/movies on your computer and have itunes not recognize this change? Only after you go to play the file does it recognize that it is not there.
Program would improve functionality of itunes by recognizing file location changes on an individual file basis and update itunes database with new location or remove file from itunes database upon move completion. Presto! No more missing itunes entries. Problem is figuring out what to do if you've copy/deleted the file(s) instead...