I just really hope that Amazon at least has it set up so that the really important stuff goes to actual, trained SREs. They could set it up so there are queues for things that aren't business critical and have a very loose SLO that get assigned to the new grads. Or, the new grads get paged when the error rate for the service is 1% and if it gets above 3% someone who knows what they're doing is woken up. If say all issues with Amazon's Route 53 DNS service is shunted to new hires, AWS would be going down constantly.