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.