Manufacturers are constantly trying to stay ahead of the curve with improving security systems, but the technology used in car theft crime evolves very quickly. Mercedes-Benz released a statement that said, "On our latest cars we now offer our customers the option of deactivating the radio signal with two clicks of the key." I can't answer your question as to why keys don't have certain security features because we simply don't know. A few manufacturers have mentioned not wanting to publicly discuss the measures they take to increase security because then car thieves could use that same information to exploit security systems. However, it's hard to say how much is actually being done to counteract keyless theft.

I always advise a Faraday bag or steering lock to secure cars because unfortunately with car theft, if there's no one to claim from (which there usually isn't), the claim will be registered as a fault claim by your insurer. As happened here: www.honestjohn.co.uk/askhj/answer/98507/my-car-was...m-