Hey David, That's a great idea.. Just to stress your point, this keeps both parties informed if a PR has become stale. So, the reviewer would know that there was some PR which was being reviewed but due to inactivity it got closed so maybe time to relook and similarly the submitter.
And yeah, any stale/unused PRs can be closed straight away thereby reducing the load on reviewers. I have done some work on kubernetes open source and they follow a similar paradigm which is useful. Thanks! Sagar.
