When do reforms meet fairness concerns in school admissions?

We study a series of reforms of school admissions mechanisms motivated, among other reasons, by fairness concerns and vulnerability to manipulation. Before the reforms and after, the mechanisms were vulnerable to preference manipulation and induced blocking students: students who miss desired schools despite having higher priority or seats left empty. We demonstrate that some of these reforms improved fairness by adopting mechanisms with fewer blocking students compared to the preexisting ones, while several others did not. We identify preexisting mechanisms where fairness consideration was more of an issue than vulnerability to manipulation and those where it is the reverse.