I've never actually tried it, but I would expect customer service to be able to move the car out of the way or push it to someone who can remotely pilot it.

Again, the main issue is that these things can cause problems with nobody is in the car. It shouldn't even be a debate. Emergency services should have a key that unlocks them and allows them to be commandeered. Everyone inside is being filmed all the time, so anyone going for a joyride is being watched, the car could be shut down remotely, and the person could trivially charged with a number of felonies, and then that access key could be removed.

If Waymo can't play well with emergency services, then they've got long term sustainability problems.