Sometimes yes, but they may or may not let you through if you can't answer their questions.

I had to do it once and just barely got through. They had to phone in and then ask me several questions that were rather ambiguous. Sort of like credit check questions but with some other strange stuff mixed in. The only specific question I remember was they asked me to name any churches or schools nearby my home address.

Then I had to get a very invasive patdown and they had to take every item out of my bag and check them all individually.