I usually try to help. Strangely enough I was in the following situation just last night.
My wife had her gall bladder removed and I waited for 9 hours. Finally, at 9 pm, they released her and told me to bring the car around. It was pouring rain and there were two young women in the parking lot who waved me down. They needed a jump (there's a straight line for you jokers). I told them my situation and that I couldn't help. They were understanding but I really felt bad that I couldn't rescue them.