> If we choose to keep this behaviour, I will have to revert my commit on mbcs 
> codec to be consistent with os.listdir(). Or at least patch 
> PyUnicode_EncodeFSDefault and os.fsencode() (use replace error handler) and 
> PyUnicode_DecodeFSDefault and os.fsdecode() (use igrore error handler).

I think trying to emulate, in Python, what the *A functions do is
futile. IIUC, disables WC_NO_BEST_FIT_CHARS, and may do other stuff
which apparently is undocumented.

However, I fail to see the relationship to this issue. Having the MBCS
codec support strict mode is a good thing.