There is no way to stop a determined thief, but putting in extra layers of defense may cause them to look for an easier target and will stop opportunists. If your trailer for instance, is attached to your vehicle, but left unattended, it is a simple matter for someone to unhook your trailer and connect it to their vehicle and drive off. This will stop that unless they have brought special tools to defeat this wheel lock. I also use a hitch lock in addition to this wheel lock when the trailer is not attached to my vehicle. So far, so good. Just don't forget it's there and try to drive off! Ask me how I know.