Delivery robot drives through a closed off LA Crime Scene, could easily be filled with explosives and remotely detonated or by the robot itself when detecting police text on their jackets/T shirts etc, etc.
If you imagine that, believe me someone somewhere though of something even worse.
That's because everything for good can also be used for bad and the humans are a race that can't be respectful of others and be respected.
There is always some conflict going, being religious or ideological anywhere in the world, from a simple assh*le who crossed in front of you too close in the traffic and flipped you the middle to a religious/political zealot giving/following orders to kill.
But that's offtopic...