Hm, I think you've mischaracterized me then. I do plenty of funny stuff with git in CI, but am usually able stick to modifying the repo in the way humans do. Maybe this is why I've mostly avoided edge cases over the years.

Though I have to say, for your examples (generating statistics and automated builds), read-only operations generally suffice for me, aside from pushing tags. I prefer to implement pull-based deployment if possible, and only allow release branches to fast-forward.