George Pullman owned both a company which built railroad sleeping cars and the town in which its workers lived. Pullman the town reflected the beliefs of Pullman the man, with large houses for managers, middle-sized houses for craftsman, and small houses for laborers. Pullman also provided recreational facilities, schools and a store which accepted the scrip he paid. And he owned every square inch of it, as employer, grocer and landlord.
This worked fine (maybe) til the depression of 1893. When the company's profits dropped, Pullman chose to cut wages and then fire workers while leaving unchanged the rent they owed and their debts to the company store. These tactics led to the Railroad Strike of 1893, which came so close to succeeding that Pullman had to call in the real government to put it down. He persuaded his friend President Grover Cleveland to allow him to put a Pullman car on every mail train, whereupon the president declared the strike was interfering with national security in the form of mail delivery, and called out the National Guard.
No wonder Pullman had to be buried in a coffin covered in tar paper and asphalt, enclosed in a room-sized block of concrete, reinforced with railroad ties. Workers probably wouldn't have desecrated his grave, but if you'd been hated that thoroughly and justifiably, would you take chances?
And so to Ferguson, where the town and state authorities believe a possible grand-jury decision justifies building barricades and calling out the National Guard. No one knows whether the grand jury will indict the police officer who killed an unarmed teenager; no one knows what the reaction will be if it doesn't. But those in charge in Ferguson and in Missouri can at least guess how thoroughly and justifiably they're hated. So their "preparation," which assumes that rioting is the preferred activity of African-American citizens, is actually a reflection of their own guilty consciences. If they'd treated their black citizens better they'd have nothing to fear from them now. Instead they await their punishment.
Just like George Pullman.