If you don't like the idea of PIN to drive and are only concerned with repeater attacks, you can disable passive entry. When passive entry is disabled, the car will only be able to start for a brief period of time after receiving an unlock signal (double-click on cabin) from the fob. If you have automatic doors, and you leave them enabled while passive entry is disabled, the driver door will not open automatically until the vehicle is unlocked (including by opening an FWD, which will not allow the vehicle to start). That isn't to say that it's impossible for someone to record a double-click and replay it, but if that is even possible (I don't know what security the button press signals have, if any), you would have to be more specifically targeted before it could occur.