So, if you're under oath, you're not allowed to lie.
And if you're read into an SCI program that controls the disclosure of the existence of such access, you're most definitely not allowed to say anything about it (or, in many cases, even acknowledge that such a thing exists).
There is no way someone would risk perjuring themselves OR disclosing classified information under oath.
I wonder if it could be construed as disclosing classified info by taking the 5th when asked. You didn't say anything, but did you say anything without saying anything?
There is no way someone would risk perjuring themselves OR disclosing classified information under oath.