I have. A close friend was a candidate for a job at the Jet Propulsion Lab in Pasadena, California and two men came to my work one day and interviewed me about her. The interview was quite lengthy. They wanted to know EVERYTHING I knew about her and I was honest and told them what a really great person she was as far as I knew. I don't know how many people they interviewed but she got the clearance and the job and she never could talk to me about the work she did.
