There has been a recent upsurge in car key fob 'signal jamming'. Car thieves can use a key fob signal blocker (easily purchased for as little of £30 over the internet) to jam the signal from the key fob to the car when we lock our cars. The car is then left unlocked for them to enter at their leisure whilst you are away from the vehicle. This is a double whammy as insurance companies are reluctant to pay out as there is no obvious sign of forced entry. When parking your vehicle, always double check the handle manually after locking using your key fob and remove any valuables from inside the car.
Another way in which car thieves can steal your car is key fob 'code grabbing' which goes one stage further than signal blocking. This device allows a car thief to remotely collect the car's unique code and records it to allow the car thief to enter your car at any point in the future. An indicator that your code has been 'grabbed' is when you lock your car it does not lock on the first attempt and does on the second attempt. This is a sign that your code could have been stolen and your car is now vulnerable. This 'Roll Jam' system works with any wireless locking mechanism including electric gates and garage doors. It is worth noting that some cars are completely keyless and these are extremely vulnerable to theft of the entire vehicle should their unique code be stolen by a code grabber.
If your car has had its code has been grabbed, the only way to ensure that the car cannot be entered or stolen in future is to have the key fob reprogrammed by the manufacturer. This can prove costly and in any case the owner may well not be aware that their key fob code has been stolen. #cartheft
Kent Online News Article on Car Crime uk