For those saying that the parent comment is crazy, or not applicable to "real businesses" - nearly every production push at Google is done during the normal workday hours of the respective development team (which means most of them happen between 9am-5pm PST).
The benefit of having the engineering team around to troubleshoot smaller-scale issues before they turn into large-scale outages vastly outweighs the small benefit of potentially moving the extremely rare massive outage to a less busy time of day.
The benefit of having the engineering team around to troubleshoot smaller-scale issues before they turn into large-scale outages vastly outweighs the small benefit of potentially moving the extremely rare massive outage to a less busy time of day.