[CWuestefeld]

services that should be unrelated to S3 such as SES were impacted

I don't think this is particularly surprising. I'd already pretty much assumed that, e.g., a package of code for a Lambda function would be housed in an S3 bucket somewhere.

What's really surprising to me is how many of those buckets appear to live in US-EAST-1, and aren't able to keep functioning in a catastrophe by failing over to a different region.

[kondro]

You specify the run region for each of those services and all the other components get restricted to those regions too.

We're in ap-southeast-2 (Sydney) and none of our services were impacted yesterday.