A terrible "feature", since it means someone can steal your car just by relaying the signal from outside your home at night, or an accomplice walking near you as you're entering the grocery store, etc.

I've become a big believer in leveraging some security features of the physical world, as it seems it's been long enough that everyone's forgetting Therac-25-style problems. (Or, perhaps more accurately, nobody cares because they aren't liable.)

It's not as bad.

Modern keyfobs actually detect motion and if they are motionless for a while, they stop transmitting the signal to both save battery and prevent such attacks.

For old keyfobs, you can get a battery sleeve with integrated motion sensor which does the same (cuts power when fob is not in motion for a while).

Alternatively, some cars let you disable the feature and just use the keyfob as you would use an older one - then you habe to push the button anytime you want to unlock the car.