Any two people are in a less-extreme but similar boat: if someone puts up a bad diff and someone without a stake in the code accepts it, they had better hope to hell nothing goes wrong.
SEV review is a remarkably enlightened process for what it is, but you do not want to sit there explaining to extreme-seniority people why you YOLO'd something into Presto without buy in from a Presto hacker with your manager sitting behind you already thinking about how much this is going to get harped on in calibration.
The `OWNERS` file at FB is in `hg log`, but it's there.
Because it was more disciplined, those commits could be automatically marked for later review.
In the bad/fun old days of extremely small on-call loop, a less clear/organized escalation chain, and fairly "roll your own" per-team tooling, once in a blue moon a whole business unit would be down because 10k machines were crash-looping and you just needed `if (NULL == ptr) return;` on like one line to end the carnage. There are exceptions to every rule I suppose.
But in 7 years at FB I think I force slammed someone else as reviewer with merely their verbal approval in the middle of the night 2 or 3 times, and never after like, 2015.
They mail you the shit off your desk for playing games with any of that stuff, and it’s thoroughly, thoroughly checked.
They finally added a "final review" step to ensure that someone eventually takes a look at these changes after the initial accept, but that still occurs several days after the commit.