Yes, I've done that, because the reflog keeps more than just commits. It also keeps checkouts, merges, steps in rebasing, etc. So I've checked out a HEAD@ ref,

Yes, I've done that, because the reflog keeps more than just commits. It also keeps checkouts, merges, steps in rebasing, etc. So I've checked out a HEAD@ ref, when I made a mistake in merging or rebasing.