My first car was a 1981 Subaru. It had starter issues from hell and I would offer classmates a ride home if they gave me a push so I could pop the clutch. I had major issues with locking the keys in the car, so I would leave the back window opened just enough for me to fit my arm through. It didn’t rain much where I lived, so I didn’t really worry much about water getting in. It leaked anyway, window up, window down, didn’t make much of a difference.
I continued to have problems with locking my keys for the next several cars I owned (leaving me with the expert ability to be able to break into a car) until I finally got a car that had a key fob. Since I’ve been able to lock a car remotely, I’ve never since locked my keys in the car.