If valve doesn't do code reviews, and if pull requests are actually blindly accepted (is that actually a thing? Do people ever actually blindly accept pull requests?) I don't think I have the wherewithal to give a useful response.
>is that actually a thing? Do people ever actually blindly accept pull requests?
Speaking only for myself, I've seen it with internal git repos at companies that have some name recognition. Obviously they'd never want it known that this happens, but it does.
So why does it happen? In the cases I saw, it was usually when people responsible for code reviews had "other things on their plate", and rather than hand off the review to someone else, they just merged it. During heavy pushes to get a build out the door, I saw a lot of this happening. Since I never said anything, I suppose I was part of the problem.