One of my research assistants had her computer stolen with all of the data that she had been coding for me on it. Backed up? Nay. Despite www.dropbox.com, despite the ease with which one could use an i-pod as a hard drive, nope. I am paranoid myself precisely because I had a desktop machine stolen from my office (actually, I have had two machines taken from my office). I remember working on my dissertation twenty years ago (oy!) and making sure I had the stuff on multiple disks in multiple places.
I didn't think I had to alert 21st century students about the need for backing up. I was wrong. So, folks out there who rely on research assistants--remind them that it pays to take care of one's work.