For my husband he was fortunate enough to have it on camera. You can clearly see the car zooming by real fast in a 15 mph small turnaround lol.
The way they will fight it is that, even if you are backing out. If the person is coming on the mainstreet (in parking lots anyone coming through is considered main street driver), then the person reversing have to wait, or pull back in and let them pass. That is how they will most likely argue. It sucks, but that is how bogus some of this stuff is. Like if you're driving and someone suddenly cuts you off and brakes suddenly, if you hit them, many times the cops and insurance will say you were at fault since you hit them.