Not a questionnaire, but a friend's ex-DH applied to the FBI, and used me as a reference. So I had a real live, (very cute) FBI agent come to my hosue to interview me and ask questions about him.
Stuff like "does he live beyond his means" which I get, and one which, although I don't recall exactly what it was, was something along the lines of did I think he was loyal to the USA, etc. (this was well before 9/11 too) I wanted to be snarky in my response, as her DH was a grad of a service academy, and ex-military as well. He was about as American as one gets. He was accepted, but chose to go work for NSA instead doing something he could never talk about.