> I'd rather not have a new option here ...

Perhaps what I'm suggesting here is that I don't see any reason for "sudo pip install ..." into a distro-installed Python to ever need to work, and would be quite happy for it to just fail miserably every time (which is already the case for the Windows Store distro of Python).

Admin installed all-user packages is the expert scenario here, and can be as twisted as possible. Pip installed per-user packages and system-tool installed packages are the defaults, and the more easily those can be overridden by a file in the distro, the better.