This sounds nice, but makes zero sense. Direct short will be fused and isolated, otherwise UPS banks would get damaged (maybe even explode).
Edit, and reading further there it is:
>"If there was a ground fault in the facility, the impacted branch circuit breaker would open and the rest of the facility would continue to operate on generator and the servers downstream of the open breaker would switch to secondary power and also continue to operate normally. No customer impact."
The rare failure mode that can cost $100m looks like this: when the utility power fails, the switch gear detects a voltage anomaly sufficiently large to indicate a high probability of a ground fault within the data center. A generator brought online into a direct short could be damaged. With expensive equipment possibly at risk, the switch gear locks out the generator. Five to ten minutes after that decision, the UPS will discharge and row after row of servers will start blinking out. This same fault mode caused the 34-minute outage at the 2012 super bowl: The Power Failure Seen Around the World. Backup generators run around 3/4 of million dollars so I understand the switch gear engineering decision to lockout and protect an expensive component. And, while I suspect that some customers would want it that way, I’ve never worked for one of those customers and the airline hit by this fault last summer certainly isn’t one of them either.
http://perspectives.mvdirona.com/2017/04/at-scale-rare-event...