This sounds pretty bad to me.
Consider the following scenario:
When you're away from your Smart, the battery dies. (perhaps you left your lights on?)
You return to your car, discover the dead battery, unlock the car, read the manual, and cry in frustration.
Then you decide you need to go for help for jumper-cables, or to call a friend, whatever. At this point, you cannot secure your car to go for help??!
That is a big WTF to me. You should always be able to secure your car.