I know it's considered bad to assign two Unicode values one glyph, but I can't remember why. Someone recently suggested to me that it would be a good idea in the case of all-caps fonts, to double map the uppercase as to eliminate the superfluous lowercase set. It sounds like a disaster, but I couldn't explain specifically why it's so bad. I recall a discussion about this on another type design forum but I can't recall the details. It's bad, right?