If a repo is configured to ignore stale reviews, every commit to a PR made against that repo means that the PR needs to be re-reviewed. Re-reviewing is costly, and not all commits are worth that cost.

One example of such a commit is a simple merge. During a PR's lifetime, the PR's target branch (typically, repo's `master`) might be merged into the PR multiple times. Usually, such merges are trivial and would effectively be performed by Skara automatically if the PR didn't have them in the first place. For such commits, it makes sense to not require re-review.