My guess is never. I can't imagine any company that would want her on their board.
http://www.cnn.com/2002/ALLPOLITICS/12/13/kissinger.resigns/
I mean, sure, the truth eventually came out. But I doubt "honesty" is at the top 10 priorities of most big companies.
Holmes on the other hand was directly defrauding investors, why would you want her on an executive team/board trying to get investments?
If I work for Apple, and I sneak a glance at their balance sheet, and short its stock, I did not rob APPL shareholders. It's still illegal, and insider trading (Because otherwise, I'd have an incentive to actively sink the company, while benefiting from a short.)