Victor, people set "LANG=C" for all sorts of reasons, and we have no
control over how operating systems define that locale. The user
perception is "Python 3 doesn't work properly when you ssh into
systems", not "Gee, I wish operating systems defined the C locale more
sensibly".

If you can come up with a more sensible guess than UTF-8, great, but
believing the nonsense claim of "ASCII" from the OS is a
not-insignificant usability issue on Linux, because it hoses *all* the
OS API interactions. Yes, theoretically, using UTF-8 can cause
problems, *if* the following all occur:

- the OS *claims* the OS encoding is ASCII (so Python uses UTF-8 instead)
- the OS encoding is *actually* something other than UTF-8
- the program encounters non-ASCII data and writes it out to disk

For fear of doing the wrong thing in that incredibly rare scenario,
you're leaving Python broken under the C locale on *every* modern
Linux distro as soon as it encounters non-ASCII data in an OS
interface.