Two: I have, honestly, always assumed that intelligent people question and pick up on mistakes through reading or simple exposure in life. Thus, I figured that people who didn't pick up on things like proper usage of "she and I" vs. "me and her" through exposure to people who speak correctly (either in writing or just talking), were probably not unusually bright. It isn't about my feeling like education and intelligence are the same thing. It is more about assuming that intelligence and self-awareness are correlated and that intelligence tends to cause people to self-correct when exposed to 30 people responding to your post who use the same phrase you did but correctly.
FWIW, my thesis adviser (who is a very intelligent man) STILL cannot spell my name correctly even though every email I sign my name on it and people have even mentioned it to him. He definitely knows me very well (and we get along well too) but he just never picks up on it. Honestly, some of the smartest people I know are significantly less observant about things like that. Then again I work with very math orientated people and I've even notice some who have very obvious difficulties when it comes to languages.
