While what you say is generally true for 1, I wholly disagree that it is always customers that do the coupling.
One more than one occasion there are AWS URLs, including redirects inside the console, that include US East 1 in the URL that were only spotted during an outage. Manually changing it to an different region allowed us to get around it but to wholely blame customers when you don't know the context is bad form.
But there are also always exceptions. I've seen US East 1 outages cause autoscaling issues in other regions including failing to start new EC2s. A real problem if things have scaled down overnight.
One more than one occasion there are AWS URLs, including redirects inside the console, that include US East 1 in the URL that were only spotted during an outage. Manually changing it to an different region allowed us to get around it but to wholely blame customers when you don't know the context is bad form.
But there are also always exceptions. I've seen US East 1 outages cause autoscaling issues in other regions including failing to start new EC2s. A real problem if things have scaled down overnight.