Imagine that you are producing a reality TV series about alcoholism. You like the cinéma vérité approach (otherwise known as the "fly on the wall" school of filmmaking), so you have your crew follow the routine of a woman, Pam, who is struggling with this disease. At one point, Pam decides to go for a drive. Before leaving the house, Pam takes a swig of vodka. She is in no position to get behind the wheel, so you ask her if she would like for someone in the crew to assist her.
She mumbles, "No, I can drive," and heads out to her Pontiac Sunbird. Fearing that the woman could be a danger to herself and others, you prevent her from getting into her car and turning it into a killing machine, right? Wrong. You let her drive off.