[vinkelhake]

That's a big if. The S3 outage in February this year showed that there are a lot of sites that aren't designed for this.

[myusernameisok]

The S3 outage was across the whole US-EAST-1 region, not just one data centre.

I know my company and a few others that are redundant within a region (ie if one AZ goes down), but not if a whole region goes down.