when we were traveling by car back in the "full service" days I never allowed anyone to open the hood or do any sort of service short of cleaning the windshield. I always stood right by the pump as the attendant was doing his thing while my wife stood outside and watched that side of the car. if we needed the restroom or a snack one of us would "stand guard" while the other ran the errand. assume the worst. now in the self-service world we live in it's not much of a problem but I still do not allow anyone to service or exam anything without my express permission.