If this happened as claimed, why would Cain be asking that his accuser be released from the confidentiality agreement? Do you really think he would want this to be publicized?
Of course, it might be just a ploy: Cain may think his "ace in the hole" is that his accuser will never go public.
But, I think it's just as likely that this story was manufactured by someone with an axe to grind. These "witnesses" are remaining anonymous, too. Has anyone bothered to confirm they are who they claim?