A few notes and questions: 

- Slide 7, line 1: that's "members" with an S 

- Slide 20: I think we should note explicitly that one issue is that, for someone to discern a difference between code points (or between diacritics), they have to be aware that both exist.  All of us operate under than handicap that we know too much -- we are familiar with all the two dozen or so diacritics, we know what they all look like, most importantly, we know that they exist. The average user, even the average "very careful user" is familiar with perhaps a half dozen of them.  As a result, he doesn't realize that he might want to look for some kinds of differences. 

- Slide 21:  I'm not sure what you are getting at here.  As far as I am aware, the problem with stacking diacritics is that, with some of them, the combining diacritic doesn't combine in some fonts (e.g. Courier New).  And with others, it combines with the following code point, rather than the preceding code point.