I dont carry a slim jim. 
Her car was a newer jeep, I dont think she realized that cars are keyed differently. 
Mine was an old 92 Mazda, my key definitely would not work. 
I was more worried she would snap my key. 

Satosora

alter_native

Locking Keys In Car

Not much else that can be done. I have found my way into locked cars a few ways over the years but usually needed a tool. I have used a Saturn key to open a Honda before. On older cars, it was easier to use the wrong key on a car and get it open. 