A good example was the AWS S3 outage that occurred when a single engineer mistyped a command[0]. While the outage wouldn't have occurred had an engineer not mistyped a command, that conclusion still would have missed the issue that the system should have some level of resiliency against simple typos - in their case, checking that actions that wouldn't take subsystems below their minimum required capacity.
[0] https://aws.amazon.com/message/41926/