In my neck of the woods the Police don't fault anybody in a private parking lot such as a grocery store, strip mall etc. I found that out when I was backing out of a stall, was 3/4 of the way out and some guy going way too fast and not paying attention hit me. I stopped got out of my car and the guy was telling me it was all my fault because I was backing out and therefore he had the right of way. Well, just at that time, a guy pulled up in a truck and told me he witnessed the whole thing. He said the guy who hit me was going way to fast and not paying attention. That was pretty much what I thought as to what happened since I was slowly backing out and was nearly out of the stall, when out of nowhere, this guy tags me. I decided to call the cops since nobody would agree to who was at fault. When the cop showed up, he told me all can do is take a report and issue no tickests since the parking lot was private property. Basically, it was going to be up to our insurance companies to make a decision. Luckily I had the witness who gave me his name and phone number, and told me he would testify on my behalf.
I called my insurance company, as well as the guy's who hit me, and both said that I was at fault due to the fact I was backing out, but once they heard the story from the witness, they changed thier minds pretty much. In the end, I was considered 20% at fault due to the fact I was backing out, but the other guy was 80% at fault for going to fast, innatentive driving, and failing to avoid an accident. My insurance company told me that if I didn't have the witness I would have been 100% at fault, so I got really lucky.
In the end I learned that if there is no witness, some a-hole can pretty much intentionally ram a person backing out to get money from somebody elses insurance company. My agent told me that actually happens frequently these days.
After my experience, I made it a habit to park way the hell away from everybody else, and definitely not in stalls right in front of the store where people cruise too fast through the parking lot. It just isn't worth the few extra steps it saves getting from my car to the store.