My Philosophy on Alerting: Observations of a Site Reliability Engineer at Google
Why does a company the size of Google even have call rotations? Shouldn't they have 24/7 shifts of reliability engineers who can manually call in additional people as and when they're needed?I can totally understand why SMBs have rotations. They have less staff. But a monster corporation? This seems like lame penny pinching. Heck for the amount of effort they're clearly putting into automating these alerts, they could likely use the same wage-hours to just hire someone else for a shift.   
Heck with an international company like Google they could have UK-based staff monitoring US-based sites overnight and visa-versa. Keep everyone on 9-5 and still get 24 hour engineers at their desks.