My Fraternity's cook, when I was in college, was a former fellon. He worked for us for a few years before he told me about his background.
I don't remember the details, but we had a conversation where he mentioned he had experience in IT. Eventually he very briefly mentioned some high level details about his criminal record when the conversation drifted around "so if you were making big bucks, why are you now cooking for us?"
I personally appreciate that he warned me about the consequences of the super-illegal (but "grey morality") thing he did. But, I must agree, it's best to keep things like a record quiet as long as possible.
I don't know if other fraternity brothers knew about his background. It seems like the kind of thing that would be kept quiet until someone started veering into the super-illegal (but "grey morality") area that got our cook in trouble.