Good points jay-h, many people tend to forget the simple ways to protect yourself and your belongings. If people don't know you have something of value they are less likely to come looking for it.

Crooks are looking for easy money...they are, after all, crooks and want to get something by not working to get it. If you don't leave your laptop out in the open, they'll keep looking elsewhere for something easy. It also goes without saying that if you really want to safeguard your laptop, don't leave it in the car.

Obscurity may not technically be "security" because it does not stop someone from doing something. However, it does play an important role in the overall security strategy. Obviously, it is not something you would rely on wholly but not to be discounted either. Remember the old saying "Loose lips sink ships!" And now we have "Information is power." This power can be used to sink ships just as it may be used to save them.