I have heard some say that such a lock will not stop a thief. Honestly, no lock will stop a determined thief, so we'll skip it. I view this lock as a deterrent, not a total defense. A potential thief will see this and move on. This eliminates the simple possibility of someone simply rolling your bike away. Will some tough guys be able to get him in the back of a truck? Yes. Can they pick the lock and remove it? Yes, but both require planning and additional time. It is very easy to use and stays on the brake lever. While this may not be the "best" option, hopefully it will drive the would-be thief to the nearest bike, not yours.