The way i look at it is that if you dont have the sticker on then they are going to attempt to steel it, ( damage to your car )if it does have the sticker on it may stop them from attempting to steel it. ( no damage to your car )
i dont think it would be easy to find, its only as big as a stick of chewing gum and can be fitted Anywhere within the wiring loom, under the bonnet, within the passenger compartment or even the boot, that's a lot of places to look