October 2013, I called my credit card company - Citicards - to pre-authorize an extra-large upcoming charge (donor eggs from an egg bank for IVF). The first 3 questions were fine, but then the guy asked, "The payment you made in April of this year, what are the last 6 digits of the account you used for payment?" Um...that was 6 months earlier and we had closed the account. We had no checks or deposit slips left that showed the entire account number, just statements with the last 4 digits. I knew those last 4 digits, but that wasn't good enough; he kept insisting that he needed the last 6 digits. I kept telling him, the account is closed and I do not know those extra 2 numbers, I've given you all that I know.
He finally moved on by asking an extra 5 questions. Thankfully I got those correct.
His last question was, "How will the company be billing this charge?" (gas, groceries, etc.). Um...how should I know? I said I thought it would be a medical expense, he then asked what kind (doctor's office, hospital, etc.). I got frustrated and said, "I'm buying body parts on the internet." He was silent for a moment, then said, "Okay, no worries, this charge has been authorized."
ETA: The bank were I have my oldest checking account always asks these questions when you sign on via Internet. The one question I always get is "In what state was your Social Security number issued?" In the four choices, it always gives me Illinois (where I was born) and Connecticut (where I moved at the age of 2 and grew up). I assumed that the number was issued in IL, so I always checked that off and I've been able to get into my account. My mother told me a week or so ago that no, she didn't even think of it when I was born and the number was issued in CT after we came here.