Slightly Stressful Moment of the Day

I had a slightly stressful moment at the grocery store this afternoon when I walked out to the parking lot to get into my car. I put my key in the car door, unlocked the car, and opened the door. As soon as I did this, the car panic alarm began to honk loudly. I didn't know why my car was doing this until I reached in the backseat to begin unloading my groceries and I noticed that this WAS NOT MY CAR!!! How embarrassing! I quickly shut the car of which I was trespassing and used my key to lock the door back! The elderly people walking by could only stare at me as I sheepishly explained that it wasn't my car but my key worked on the door! With my head low, I quickly walked to the next aisle where my car was parked in the exact same space (just one row over), hoping that the owner of the other car had not seen me. I can't help but wonder if my key would have worked in the ignition.