> I hope we normalize just admitting when most of a piece of code is AI generated.

People using AI tools in their work is becoming normal. In the end, it doesn't matter how the code is created if the code works and is otherwise high quality. The person contributing is responsible for checking the quality of their contributions. Generally, a pull request that changes half the system for no good reason without good motivation is clearly not acceptable in most OSS systems. Likewise, a pull request that ignores existing design and conventions is also not acceptable. If you do such a pull request manually, it will probably also get rejected and get told off by repository maintainers.

The beauty of the pull request system is that it puts the responsibility on the PR creator to make sure their pull request is good enough. Creating huge pull requests is generally not appreciated and creates a lot of review overhead. It's also good practice to work via the issue tracker and discuss your plans before you start the work. Especially with bigger changes. The problem here is not necessary AI but but people using AI to create low quality pull requests and people not communicating properly.

I've not yet received any obvious AI generated pull requests on any of my projects. But I've used codex on my own projects for a few pull requests. I'd probably disclose that fact if I was going to contribute something to somebody else's code base and would also take the time to properly clean up the pull request and make sure it delivers as promised.