There has to be a lot of mentions about the purpose and approximate workings of a car wash, as well as lots of literature that shows that when you drive somewhere, your car is now also at that place, while walking does not have the same effect.

It's then up to the model to make the connection "At the car wash people wash their car -> to wash your car you need your car to be present -> if you drive there your call will be there"

No, I think they have explained this to each other (or something like it). But as you suggested, discussion is a lot more likely when there are corner cases or problems.