Best Practices for Testing Zone Redundancy
The way the story goes is that in the old days Amazon used to cut power to data centers so they could see if their services were actually redundant across different data centers; and that they only abandoned this practice when EC2 customers started to complain (no matter how many times they were warned their instances might disappear without notice). This story may be apocryphal, but you don’t need to be worried about power loss outages in order to have a given data center go down.