Oh, yes. there's a grain of truth in that. Rarely did you see anyone not black in Harlem. If you did, it was so they could get their drug of choice, which was easily accessed through the entertainment in these clubs. It really picked up in the 20s, when women's dress lengths rose and a new type of woman, the flapper, was born. She was most definitely testing the boundaries and her parent's patience with what they saw as her new immorality. Prohibition hit in 1918 and things went underground. But getting back to your last sentence, messing with a white woman/man whose parents were wealthy and politically connected could get you into trouble.

You know, people really do not give jazz/popular/blues music the credit they deserve for bringing two types of people, who would have never met or socialized, together.