Criminal defenses in law?

Roberta Jones is an exotic dancer in Ft. Myers and is performing at a bachelor party. She is arrested for soliciting prostitution after an undercover police officer offers to pay her $50.00, and she agrees to perform a specific act with him in private. Ms. Jones erts that she is being singled out for persecution based upon her color (she is Black); she further erts that many white exotic dancers performing at area bachelor parties are paid for private acts, but our never prosecuted. Might she have a meritorious defense? What is the defense, and why should she raise it?