I wonder if this is done because people have a tendency or something to always create resources in 'A' (or some other AZ) and this helps spread things around.
And if I would have read the page the link points to better, that's exactly the reason
Availability zones are not guaranteed to have the same name across accounts (ie. us-east-2a in one account might be us-east-2d in another). You would need to use the AZ-ID to determine if they are the same.
AWS availability zones (so like us-west-2b rather than us-west-2) are not the same between accounts. us-west-2b for you is something different than us-west-2b for everyone else.
You'll need to see which availability zone ID (e.g., use2-az3) corresponds to each zone in your account: https://aws.amazon.com/premiumsupport/knowledge-center/vpc-m...
edit: AWS identified this as a power loss in a single zone, use2-az1.