I was with you until the last part. Well, ok, I'm not smart enough to understand the sentence that precedes the last part, but I jumped ship at the last part. There's a million reasons to prefer Harvard over Yale. Yes, most people who have the choice tend to go to Yale. But Yale isn't necessarily the better choice if: you hate New Haven, you really care about IP/internet stuff, you want to do a JD/MBA, you have family reasons to be in the Boston area, you want school leadership that is more politically balanced (at least in its hiring), you want a more comprehensive 1L curriculum, you like the idea of more faculty or more class options, you like ice skating or volleyball, you are certain you want to work internationally, you care how many books are in the library system, you want the motivating factor of grades, you appreciate the institutional history of being where modern law school education was invented, etc. These aren't equally good reasons to prefer Harvard over Yale, but they are reasons. If you really care about some of them, you might be better off, ex ante, at Harvard.
Eh, poorly written and hard to parse, but I thought the point would be clear since you're a philosophy guy. We both agree that uncertainty drives many prospectives to Yale. Your reference to risk aversion implies (or at least so it seems to me) that you think that, in doing so, they're employing a decision-making process that doesn't equally account for the pluses and minuses of each possible outcome, scaled to probability. Maybe they don't--but I think they'd end up in the same place if they used a standard expected utility calculation.
Agreed that personal reasons or particular academic focus could tip the balance in favor of H. I just don't think that ends up happening very often.
You're not the first to mistakenly assume I know something. I'm surprisingly bad at knowing things, least of all philosophy. Now that I understand the point somewhat, I'll say something about it. I didn't mean to say that law students are irrationally risk averse. They might be precisely as risk averse as they ought to be, or perhaps their sensitivity to risk should simply count as one of many axes for preferences. I just think they are risk averse.
As to how often rational actors should choose Yale, I think it's really hard to say. I think it's at least possible that the differences between the schools, and in particular the differences in expected outcomes for individuals choosing between the schools, are very small compared to the perceived differences, mostly due to ranking and selectivity. If perceptions really do outpace reality, then you'll probably have a nontrivial number of people ending up at Yale who would be just as well off or better off at Harvard. This kind of perception gap probably skews much more strongly toward Yale, though some will have an inflated perception of Harvard's superiority in X.
At the end of the day, because I believe that the differences are probably marginal for most, it won't matter if they chose the "wrong" school.
On a related note, I think one or more people transferred from HLS to YLS this year (probably every year). This is an odd choice to me, for various reasons.