An identity check system used for VA loans uses your credit history to come up with secret questions. It's multiple choice and they auto-generate convincing other answers and/or some questions are completely auto-generated "ringers" which you must answer none of the above.
(The questions are things like "Which of the following banks have you had a car loan through?" "Which of the following addresses have you had?")
Problem is, I have very little credit history, so the likelihood of getting a question I can answer is near zero. On the other hand, whatever source they're using also has some assumed-real but actually incorrect associations for me (again, because I have little real credit history, the credit check system seems to be "grasping at straws" to generate a report on me).
So I couldn't just answer "none of the above" for all of the questions, because at least 1 out of each batch of 4 was not an auto-generated made up question but a real question asking me to guess what mistaken answer to it they have on file. After several tries / refreshed batches of questions that were all unanswerable, it locked me out of the system.