On an old '85 Ford V6 I left the key “on” for about 20 min. while having problems loading my boat on the trailer. When I went to restart the motor it would crank but not start. I had burned out something in the primitive electronic ignition. Not easy getting the car and boat towed up the ramp. Lot’s of other boaters weren’t happy with me that day.
In general not a good idea to leave the ignition switch “on” without a running motor. That’s why there is still an ACC “accessories” position on ignition switches.