I think this laptop detection device is a myth. In the Star newspaper the police talked about it but until now not even one picture of it is available anywhere or online.
If you dress like an office worker, you come out of your car and don't carry a briefcase or bag with you, then chances are your bag is in the car boot. Thieves can easily make that assumption and try their luck. Or maybe you stopped the car then put your laptop in the boot, lock your car then walk off. Thieves also can see that.
Next time, leave a laptop bag in the boot. At your destination, take that bag out of the boot and lock your car. It may prevent break ins.