Review on Secure Your Laptop with the Kensington Portable Laptop Combination Cable Lock - Letter Combination Lock (K64684US) by Isaac Shankar

If you're commuting for hours on public transport or moving from hotel to hotel, this cable lock can come in handy to prevent nimble fingers from stealing your laptop, but worse, it disappears with years of data. The cable is designed to wrap around a fixed support (rail, pipe, bracket) and the lock fits into a "security slot" found on most laptops. It is no problem to pry the lock out of the groove or out of the attachment point. So it's a visual deterrent to accidental theft, but nothing more. When I'm in a hotel, I either lock my laptop in the room safe or leave it in the hotel safe.