So, Amazon has said since the introduction of EC2 that, to ensure really high uptimes, customers should use multiple availability zones and architect their appl

So, Amazon has said since the introduction of EC2 that, to ensure really high uptimes, customers should use multiple availability zones and architect their applications to survive an outage in a single availability zone. While I would question Amazon's competence if outages of any sort were overly frequent, Amazon has not had many at all and no recent cross-AZ ones. [This is correct, right?] I recognize that architecting applications to be performant across datacenters (tolerant of relatively high-latency replication), but Amazon seems to be a poster child for keeping its promises w.r.t. availability. Is my take on this incorrect?