I often used the hatch button to unlock the car. Sometimes it really is more convenient than any other available method.
What I don't understand, though, is why the car doesn't auto-unlock when I'm right next to it. I wish the auto-unlock range were several times larger than it is. and directly_in_front_of_the_car isn't as useful as right_next_to_the_rear_door.
This is my #2 frustration with the car.
I believe it has something to do with which antennas listen for your key fob. I was told there is one in the rear but for whatever reason, that isn't used to auto unlock the car. That's what one of the Rangers told me at least.