The first day I had my new Prius I drove to the Post Office. When I came out I saw my car down the line directly in front of me. I started walking toward it and thought, "I don't remember leaving the back windows open." Then I got even closer and thought, "I really don't remember leaving a big fuzzy white dog in the back seat."
My car was parked on the next row over. I'd never noticed how many Priuses (is that a word?) were on the road until I got mine.
I did use the panic button on a rental car one time. My mother had called me on my cell phone just as I parked the car at a mall, so I wasn't paying attention to what was around me. When I came back out I couldn't even remember what color the car was. I was kind of embarrassed when I did find it. It was this huge van that stood up above all the other cars around it.
Another time at a mall I would have used the panic button on my own car, but spent 45 minutes looking for it instead because panic buttons hadn't been invented yet.