I turned off passive entry in the security settings. Since you have to press a button on the fob before you can start the car, I think this is good enough for me; repeater attacks are effectively nullified, and it's a lot easier than messing with a faraday pouch and/or a PIN. Automatic doors are still on, but you have to unlock before they work, so now I can walk by the X in the garage while my fob is on me without worrying about the door opening and not closing, too. It may be possible that the car would start with a repeater attack if walkaway door lock failed, but that would be a pretty unlikely sequence of events (and one that could be nullified by always locking with the fob, too).