Thank you for raising this important issue.
The broken-windows reviews are still a new effort, so at least for now, I'd appreciate it if the meta posts discussing these questions could also address specific answers. Sometimes existing answers are fine, sometimes a minor edit will fix them, and sometimes something bigger is needed. Instead of trying to come up with a one-size-fits-all answer before we have much experience with this, how 'bout highlighting the cases where something bigger is needed? Then the community can weigh in or, ideally, help bring them into sync.
When changing a question in a way that affects an answer (which is rare outside of this effort), I leave comments on affected answers to point out the change and ask for an update. If the author has visited the site recently, I prefer to give him a chance to make the changes himself first. I recommend this here too.