This is a fun paradox: someone who graduated from {MIT, Harvard, etc.} can't say they did, since it would be elitist. They can stop mentioning their Alma mater when they realize that it sounds elitist to mention it. But then it just seems like they're not mentioning it, as a way of signaling their lack of need to mention it (their status is obvious). Once you graduate from any of these schools, there's no way not to sound elitist when asked where you went to school. You're trapped.

PS - This, of course, doesn't mean someone graduating from these schools isn't elitist. It's just that the social exchange in which they tell you their Alma mater doesn't give you any information in regards to their elitism.