There is a clean solution:
"Here's how to do it properly: use RFCs 2047 / 2231." That (a) is
backwards compatible, (b) is consistent with Best Current Practice
(RFC 2277), (c) is consistent with the Internet Architecture (RFC
1958), (d) is compatible with RFCs 822, 2822 and the MIME RFCs, and
(e) is inclusive (GB18030 users are not ostracized). Raw untagged
utf-8 does not posess those characteristics.
it's not a complete solution, because 2047 only applies to human-readable
text, and the 2231 extensions only apply to parameter values in MIME headers.