I was following a car in the San Francisco DMV parking lot. The driver made a turn but suddenly stopped. I tried to go around him, but he then started to back up to try and get a parking spot. The road is one way and wide enough for two cars. I honked, but the next thing I knew he backed up into the side of my car. The damages are minimal. If he had checked his mirrors or turned his head to look behind him while backing then he should have stopped and waited for me to pass, right? We got each others' information, but he still blames me. If it is my fault I'm willing to take responsibility, but i just want to make sure. So, who's wrong and right in this situation?