This is kind of my problem with the idea of federated sites. Instead of trusting one big central authority, you put just as much trust in one of many small ones. But your eggs are still all in one basket, and since there is no robust identity verification measures (some kind of either centralized or distributed system to distribute certificates for example), you get all of the flakiness and other problems of small communities with all of the chaos of a large one, with the considerable complexity of federation to make it all worse.