It’s not clear to me how persistent the map is. I haven’t seen anybody analyze the memory of the system. I don’t think this area was well covered by ultrasonics (I also do not know if they use ultrasonics but it does not matter).The funny part is that it DOES build a map etc
In this case the ultrasonics in the rear bumper (or cameras or whatever; it does not matter) should have seen the vehicle, memorized the location, and ensured that the area without ultrasonic coverage did not collide with the vehicle. Failing that (say the ultrasonics could not see the adjacent car when parked), the ultrasonics should have created a map when the car was initially parked, hours before summon was invoked. Just like a human. And do sanity checking to make sure the situation didn’t change while parked of course. Just like a human.
Anyway it does not matter. Obviously to anyone who has tried to use it, the system does not do most of this.
It’s clear to me with the sensor suite on the vehicle that the various collisions here could be avoided by really using the existing sensor suite plus memory. But Tesla isn’t bothering to do it (not sure why, probably limited resources to overcome the technical challenges - it’s one thing to have a sensor, it’s quite another to build an accurate picture of the environment (detect and identify narrow trees, poles, etc., things that are easy for humans) with vision and ultrasonics).