Keith Moore writes:
but if both encodings do appear without tagging, and the difference
can reliably be determined by heuristics, I do have faith that
vendors will implement those heuristics.
My "reliability" may be your "nightmare".
Wearing my GUI programmer hat, I have faith that I can provide a good
default when I need to ask the user for an encoding (say in a "file
load" dialog). It will be right better than nine times out of ten, and
when it's wrong the user can try a different encoding anyway.
Someone writing e.g. an MTA may want a tad more reliability than that.
--Arnt