Police are already using self-driving car footage as video evidence:

While security cameras are commonplace in American cities, self-driving cars represent a new level of access for law enforcement ­ and a new method for encroachment on privacy, advocates say. Crisscrossing the city on their routes, self-driving cars capture a wider swath of footage. And it’s easier for law enforcement to turn to one company with a large repository of videos and a dedicated response team than to reach out to all the businesses in a neighborhood with security systems…