In composing it, I checked with my source on the scene, Greg Farrell, to get a timeline on the passage of the Black Caucus members from the Cannon Building to the Capitol and back. According to Farrell, they left the Cannon Building about 2:30 PM on March 20th and returned about 3:15 PM. He had no reason to exaggerate.
I asked because at 4:51 that same day, McClatchy reporter William Douglas posted an article on the McClatchy website with the inflammatory headline, "Tea party protesters scream 'nigger' at black congressman."
In other words, Douglas, with an attributed assist from James Rosen, managed to interview representatives John Lewis, Emanuel Cleaver, and Barney Frank, compose an 800-word article, and have it edited and formatted for posting within a 90-minute window.
During that same 90 minutes, Douglas would have received and incorporated a press release from Emanuel Cleaver, making the easily disproved claim that he had "been spat upon and that Capitol Police had arrested his assailant."
Only two possibilities present themselves, neither of them good: Douglas had started writing this enormously consequential article in advance and/or he assembled it with a reckless indifference to the facts. A simple call to the Capitol Police would have killed the spitting story and a review of the video footage would have thrown the screaming of "nigger" by multiple "protestors" into such serious doubt that no responsible paper would have printed it.
He's got video to go with it; go see.