> that code submitted for review must follow the project's code format and conventions

...that's just scratching the surface.

The problem is that LLMs make mistakes that no single human would make, and coding conventions should anyway never be the focus of a code review and should usually be enforced by tooling.

E.g. when reading/reviewing other people's code you tune into their brain and thought process - after reading a few lines of (non-trivial) code you know subconsciously what 'programming character' this person is and what type of problems to expect and look for.

With LLM generated code it's like trying to tune into a thousand brains at the same time, since the code is a mishmash of what a thousand people have written and published on the internet. Reading a person's thought process via reading their code doesn't work anymore, because there is no coherent thought process.

Personally I'm very hesitant to merge PRs into my open source projects that are more than small changes of a couple dozen lines at most, unless I know and trust the contributor to not fuck things up. E.g. for the PRs I'm accepting I don't really care if they are vibe-coded or not, because the complexity for accepted PRs is so low that the difference shouldn't matter much.