My policy is to go to my car and then try to push the cart back to the collection area from my car. I'm really good at it. It's a cross between bowling and putting. I rarely miss but when I do, I'll follow the cart and put it away. The only exception is when I hit a parked car at high velocity. If that happens I just leave. In all the years I've gone to the store I've only hit about 35 cars.
Side note:. One time I pushed the cart across the row without realizing a car was approaching. That dude was driving too fast for a lot and that cart really took off when he hit it. It went about 6 feet in the air and rolled over 3 times. It just missed hitting a baby in a stroller. I left but in the rear view the driver didn't seem very apologetic to the mom. He seemed more confused. What a jerk.