Here's how I would answer the SSN question.

"I don't remember it off the top of my head. It's 021-something-something. Maybe 021-62, I think? Or is it 63? I don't carry my Social Security card with me."

Then if pushed, I will just make up a number with the caveat that I'm not entirely sure.

"Ma Kettle" doesn't necessarily remember her #. Better to play dumb than get into a fight with TSA over constitutional rights.