Quick update: spoke to someone at Palo Alto sales. Fremont and Service Center pickups are suspended. If you accept a direct delivery, you must prepay, and to get into the vehicle you must accept it. So you could refuse the delivery for issues you can see externally, but even if you do so you've already paid.
However, there's a new delivery center in Serramonte, and another in Dublin. If you're near the factory and had selected anything other than Serramonte, Dublin, or home delivery you've been assigned
home delivery something. It was not too late to change mine from the auto-selected home delivery to Serramonte.
Bear in mind that I've now gotten two slightly different answers. How closely the above resembles what's actually going on, I have no idea. Hopefully more info starts to trickle in as our flood of vehicles starts next week.
Edit: looks like similar news for at least one other -
Serramonte Delivery Center