I recently bought the Kensington Microsaver Keyed Lock at the Apple Store for my 15 inch unibody MBP. I need one for college. I used it once I got home and it wiggles when I lock it in. And once I take it out I found 2-3 scratches inside the hole. I'm planning on returning it. Is there a lock that someone can suggest that actually works well with the new unibody MBPs?