Hi Rob,
I'm not familiar with that CL in particular, but I would guess that this is just an accidental side effect of the work to not provide a bundled Git install. Stuff that possibly made sense with a Git we fully control makes less (or no) sense with a Git we don't. In this particular case, the code using `--system` is pretty old and we probably weren't aware of it when we made the problematic change. I would think that now we should be using `--global` instead.
I agree that we should be avoiding needing admin rights if at all possible.
If you can, it would be helpful if you can file a bug for this, so we can track the conversation and fix. I've also cc'ed the owners of that change to correct me if my guesses are wrong :).
-- Dirk