Cockburn, delighted with his recruits, noted happily that they excited “the most general & undisguised alarm” among the populace. He was certainly correct. “Our negroes are flocking to the enemy from all quarters, which they convert into troops, vindictive and rapacious — with a most minute knowledge of every bye path,” wrote an American commander in early August. “They leave us as spies upon our posts and our strength, and they return upon us as guides and soldiers and incendiaries.”- "Washington Is Burning: Two centuries of racial tribulation in the nation’s capital" by Andrew Cockburn, in Harper's.
Ironically, while Key was composing the line "O'er the land of the free," it is likely that black slaves were trying to reach British ships in Baltimore Harbor. They knew that they were far more likely to find freedom and liberty under the Union Jack than they were under the “Star-Spangled Banner.”- "Where’s the Debate on Francis Scott Key’s Slave-Holding Legacy?" by Christopher Wilson, at Smithsonian Magazine.
Oh dang, Snopes beat me to it.