RoboCop predicted the fall of Detroit before it happened, with Google piling money into Robotics seems like a short distance to a corporate branded police force stepping in where local assets are too thin to cover...
I think we're maybe 10 years away from robot police? I'd love to be wrong, but they're such a theoretically attractive solution (hey, robots can't be racist!) and so appealing to the powers that be (let's program it to give a bunch of tickets!) I don't see any way around it.