Well, not to mention that in Nevada at least, what she was doing is legal (presuming she was legally licensed there under her REAL name).
The story about the FBI interest though (if its even true), DID seem to indicate something about "conducting business across state lines" though. Their website mentions Chicago, and the article also mentions L.A.
Although I suppose I could be mistaken about the "legal in Vegas" part too, since even though prostitution is legal, I was always under the impression that (for medical/health inspection reasons) the um... sexual activities had to happen AT the brothel. I could be wrong though, hardly being an expert.