Yup. You pretty much have to do this. I love signing into my bank's bill payment system. "You appear to know your password and possess your second factor. But what's your favorite book? <all lowercase favorite book> WRONG YOUR FAVORITE BOOK IS ACTUALLY <starts with an uppercase book> NOW YOUR ACCOUNT IS LOCKED."

Even if you're using real answers, you will be locked out of your account if you don't treat them like passwords. Eventually.