So we can all learn to avoid downloading .exe files as well as files with no file type associated with them. But with respect to files with a false .mp3 extension, I don't see how that poses a threat. Because if you double click on a file like that, you're computer will try to open it with your music playing software and the software won't recognize the file and come back with an error message. So even if it's an executable file with a *.mp3 mask, it really can't be executed unless you explictly tell your computer to do so. Is there still a threat here?