One of my vehicles is a high end Benz with keyless go that I was told was ultra secure. Even the door locks are tied in, if you are carrying the key and just touch the door handle the doors unlock. When you park and walk away if there is nobody still inside the car based on the internal sensors, it senses the RFID chip is no longer there and locks the doors.
I had a tech in to do some work on our building’s keyless lock system, he mentioned my car and offered a credit card like looking RFID access card for myself that would BOTH open my office doors AND operate as a ‘car key’. To say I was skeptical was an understatement.
He pulled out a handheld device, put my key fob next to it and pushed a ‘read’ button, it beeped a conformation tone, he then held a credit card looking device, held it next to the handheld device and pushed the ‘copy’ button, it gave another confirmation beep.
Sure enough, with the card in my wallet I can go through all the locked doors in my building and operate my car just fine.