Yes, it is impossible to lock the keys inside the car. Here's a crazy note though. If you start the vehicle, then remove the smart key from the vehicle. (Say a friend exits the vehicle with a bag that has the keys in it) an alarm will sound but the car will remain running. Meaning you can drive off and go wherever you want. But once you've stopped and turned off the car, you can't turn it back on.
The alarm is audible outside the car as well. It eventually stops.