Zone IDs are meant to reconcile this. And due to the nature of my job, it creates plenty of headaches explaining why two accounts can have different AZ names fo

Zone IDs are meant to reconcile this. And due to the nature of my job, it creates plenty of headaches explaining why two accounts can have different AZ names for the 'same' place. https://docs.aws.amazon.com/ram/latest/userguide/working-with-az-ids.html https://docs.aws.amazon.com/ram/latest/userguide/working-wit... My understanding of the 'why' AWS did this for many regions was to avoid folks hammering the "first" zone they came across (a) when they either didn't care about multi-zone availability or were ignorant of the difference it made. If everyone hops in the 'first' zone, you could end up with disproportionate amounts of traffic. Either way, given how many new regions don't do this (either because they stopped, or that new regions tend to come up slowly one zone at a time), it seems they've abandoned the practice. Unfortunately, even new accounts in these legacy regions still end up with randomized mappings. I also suspect they didn't care much about this until cross-account features were offered.