Parking Lot Etiquette?

Where I am, in Austin, there’s a bunch of large vehicles: pick-ups, SUVs, Hummers, and what not. And there’s also the small cars.

So, when you’re in a parking space in a small car and get sandwiched between two large vehicles it can make pulling out quite difficult, since it’s hard to see behind you past the big dogs.

I’m curious, then, as to what the proper “etiquette” is if another car is coming down the lane while someone is trying to pull out of a spot.

If you’re driving down the lane and see someone backing out of a spot do you stop and let them leave, or do you blithely drive behind them assuming that they should be aware of you and stop?

If you’re curious why I’m asking this, it’s because yesterday I was driving the small car and pulling out from between to pick-ups. It was impossible for me to see behind me until I would have been halfway out of the spot. While backing up, someone honked so I stopped to find out who I was about to hit. When I stopped, some dork just drove past me. I’m thinking, “If you knew I was pulling out and saw me moving, why honk the horn and run past?”