This only works if the team has a very high standard and some self restraint.

Otherwise notorious code churners who are addicted to a high commit count plow through the code base, regardless of whether they are area experts or not.

If you contradict them, they cite the common ownership rule and paint you as a non-team-player.

If they introduce bugs into the release and you point it out, you are the villain again.

All in all, many of these shared ownership code bases are a breeding ground for politics that suffer from the tragedy of the commons.