> "we gave full A’s to over 4,000 students, or more than 49 percent of the people we taught [...] they hadn’t all crossed the threshold of “extraordinary distinction” that the student handbook says a full A is supposed to represent" (Furman and Laibson).

Perhaps we should look into why they received A without actually actually crossing the required threshold, rather than imposing arbitrary percentage limits. From the other side, if they do all demonstrate "extraordinary distinction", why should 29% of them suffer and not receive an A? I don't think the problem here is the number of students receiving A's, but instead what an A actually means.