Does anyone seriously expect filenames, that are not
7-bit ASCII, to be interoperable?
agreed, perhaps what is needed is a strong caveat to implementors that filenames
should be limited to printable 7-bit ascii, in a way that would discourage users
from mucking up.
A quick review of the principle international character sets supported by apple
shows that 7 bit ascii is the foundation of all of em, so it is possible for
even international Macintosh users to have meaningfull (if english-i-fied)
filenames at both ends.
Of course, this does propagate an unfortunate cultural bias, which is a
different debate.