Yep, that's a new lesson for us Smart owners... not everyone is really interested in the car. Some people want what's inside it, and will distract you by going nuts over the car while they swipe something. Same thing could happen to any other car, but a rare, attention-getting car is an easy mark for a thief like that.
I plan to definitely make it tougher for thieves to get into the car if possible, or at least to get anything out of it should they get in without permission.