[orbitingpluto]

Classical jibberish passwords are mostly muscle memory. I know I wouldn't be able to remember some of my mine of that sort after two weeks.

If you were incarcerated and you knew you might have to comply with an order to decrypt a hard drive, it might be in your best interest to create and shadow type many alternate passwords until you actually forget the important one. Then (hopefully) you're just a polygraph away from a not guilty in an obstruction charge.

[SquareWheel]

Of what I understand of the methodology used by polygraph, forgetting the password wouldn't help you out here. You'd still be intentionally misleading the police, and that would lead to the signs the polygraph attempts to detect.