One time on a summer day as a teenager I went to the grocery store with my Mom.
We parallel parked the car a ways away from other cars. We secured the car as normal and went on a short shopping trip.
When we came back out after maybe 15 minutes, all of the cars windows were rolled down completely.
We both know for a fact all the windows were rolled up when we left, and even if we had them down, there would have been no reason to have the back windows down.
Nothing was stolen, no one was around, everything appeared untouched.
This was a Nissan Murano if I recall correctly - it did have power windows, but at the time there was no fancy stuff to remote control car features outside of having a remote starter installed, which we did not have.
There was only one set of keys.
We still have absolutely no explanation for this to this day.