Footage of the parking lot isn't exactly the well oiled machine I'd expect self driving cars to achieve. If they can't figure out a parking routine in a fully controlled lot how do they manage to navigate public spaces?
Leaving aside the likely-correct sibling comment that they don't own the land, double and triple parking is difficult for robots to do quickly / safely. It probably isn't a high priority and they might be more bottlenecked by getting vehicles in or out of the lot.
I think they react to each other the same as they react to human driven cars, ie there’s no programming of “that cars another Waymo so treat it differently” it seems like one of them sees “that car is about to back in to me” so it executes “friendly honk so they don’t hit me”. When maybe there should be a “it’s another robot, so just trust them” check in the logic, especially when it’s the middle of the night.
We absolutely test code in production all the time. We test it as much as we can in test environments, but users, like real life, have a knack of doing things we just don’t expect. Phoenix and SF are effectively the limited beta test for Waymo. It has to be real world tested at some point. No test environment will ever fully mimic production.
Releasing betas is common and acceptable for non safety critical applications. There are international standards for equipment under control of software which poses a threat to our safety (IEC61508), hence why this is not allowed in many other coutries.
Of course, we don't release airplanes with software in beta, and they are statistically far less dangerous than cars. Yet cars also pose a threat to people around them who did not consent to be part of it.
They'll beep and backup a couple feet when a car in front reverses dangerously close, presumably as an alert to human drivers. Seems okay on paper.
But in these parking lots waymo can't negotiate a spot amongst themselves, leading to a chain reaction down the whole queue when the front car tries to pull into a spot, misses the mark, and has to back out/cut back into the line.