Is plausible deniability the right term here? Usually that's about the ability to deny having known about or authorised something after it's already been discovered.
I'm not really sure how you'd refer to the concept "they don't know I have it, so they don't know to ask". Security through ignorance?
I'm not really sure how you'd refer to the concept "they don't know I have it, so they don't know to ask". Security through ignorance?