All the police probably have to do to stop an autonomous vehicle is to turn on their lights. Autonomous vehicles have to follow all traffic laws, which would include stopping for emergency vehicles.
Having your car automatically and uncontrollably pull over every time red & blue lights are observed could lead to traps being set up on any backwoods road.
Edit: I really wish the news article would link to the actual source report so I could confirm it, but I bet that the above scenario is included in the FBI's hypotheticals.
The vehicles could limit themselves to only drive X miles on a public highway after the registration expires before it alerts the DMV and you receive a ticket.
I just realized something, when the majority of vehicles become autonomous, we will need less police patrolling the streets. I'm not sure if that's a good thing or a bad thing.
It's not very far fetched to do the same for other nefarious reasons.