It's very rare that I forget where I park. If I am in a large parking lot I just look at the row number. I'm good after that, and if there is another car in the same vicinity that looks like mine, I just check the back window. I have a Rolling Stones and Devo sticker on mine.
I know a lady that is light years beyond forgetful. She is one of the nicest people you could meet. She will help anyone in need. She is in her early 60's, and talks like Jan from the Muppets. Anywho, she has been known to walk around a parking lot for hours looking for her vehicle. She can be standing right in front of it, and somehow miss it.
One more story. My oldest nephew once went to Colorado with his college friends. One of his friends was from there and his uncle was leaving a black suv at the airport for them, with keys under the drivers side floor mat. They found the unlocked black suv, with keys under the mat, and drove off. The next thing they knew they were being surrounded by cops, and forced off the road. Yep, wrong car. What are the odds? They were free to go when their story was investigated and checked out.