e for being a member of a "protected class." It may seem a bit unsavory, but in business as in life, anything that is not illegal is legal.
To prevent this situation from occurring, I try to ask the following question: "Is there anything in your professional or personal background that would cause the selection officials to reject you as a candidate for cause; either for adverse performance, for some from of misconduct, or for some other reason that we haven't discussed as yet?"
Silence may indicate further probing. If this "might be" a serious concern (as per the "knock-out factors" previously discussed, with the client.)
Later with the client, I then lead with this issue, implementing the "showcase what you cannot hide" theory of marketing and sales. This is usually "unfair" to the prospective candidate yet still regrettably necessary, at times.
I hope this helps. All the Best!