I'm confused... She opened her door (shoved it ?) into the door of your car? Now, you said it was automatic, so is this a minivan? I thought those slid open, so it shouldn't have been sticking out in the way, right? What was open sticking out in her way? Or did she hit the front passenger door?
See why I'm confused??
I would like to think you both might have shown a little more compassion for the other one. It was hot. You both (presumably had cranky kids, upon leaving the pool) were trying to get loaded up and get home/on about your day. You were half done situating your kids. She was 7 months preggo (so probably pretty miserable in the heat and sitting at the pool watching her daughter) and trying to get her daughter in the car (how old was her daughter?) She probably figured she was faster than you were being. And evidently she figured correctly, if she backed out and you were still sitting there.
So I'm just wondering exactly how the door was hit. Did she go out of her way to hit it? Or did her having a huge belly and trying to maneuver her daughter into the car bump the door out beyond where she intended. Did the wind catch it? (I've had wind snatch an opening door out of my hands before, or keep one moving beyond where I let it go). Was one of you parked on top of the parking space line and there was less than normal spacing between the vehicles?
But really... neither of you said, "Oh, sorry, I'm almost done" or "Excuse me, do you mind letting me open this really quick?" You both just stewed about how rude the other one was I guess. Sad.
ETA after SWH: So because she was pregnant it was her fault she couldn't open her car door? What does it matter? What if she was just fat and couldn't fit in without opening her door wider? She couldn't get into her car b/c your door was taking up some of the space she needed to open hers. The polite thing to do would have been to SAY "Ooh... sorry.. hold on one second while I close the door" or "I'll be done in just one second" and then HURRIED UP. Kim O. measured hers... is your sliding door really only 2 inches thick? Really? You obviously were aware she was having difficulty (you say in your post she walked around to this side, then back to that side, etc) and yet you did and said nothing about it. Acknowledging that you are holding someone up can go a LONG WAY towards diffusing an awkward/rude situation. And not just regarding car doors... in ANY situation...