There's a whole kind of unpleasant but interesting topic about attacks against behavior of self-driving cars. I think I saw an earlier HN thread that suggested that they might put occupants at greater risk of kidnapping because the cars could refuse to take evasive actions that endanger or injure a kidnapper (or just violate a traffic law). This risk might be farfetched, but it may illustrate the concern about people knowing the limits that self-driving cars will respect and then exploiting those limits in some way.