Interesting topic, Steve.
It gets even more complex. The existence of the warranty affects consumer behavior. In the case of your customer he/she/it may have chosen to continue driving the car despite the overheating/low coolant warning because they were aware somebody else would take responsibility for the total damages! If they were to absorb the cost they may well have chosen the inconvenience - and lower total cost - of pulling over to the shoulder and getting a tow.
I suspect you're preaching to the choir here. Most of us drive cars that haven't had a warranty in a decade or more. That's the true definition of self-insuring!