Yes, but that's fairly well tested ground and isn't unique to this case.

Witnesses (in the sense of being called to that stand in a courtroom) are frequently asked to tell the court what they saw/heard/did, or from where/whom they received information. Refusing to answer may get them pulled up on contempt charges, and if they claim not to remember then the judge needs to decide whether they are lying.

Given the impossibility of proving (in an absolute sense) that the witness does in fact remember (at that exact moment), it's a game that witnesses are likely to get away with (hence the standard "I don't recall" answer from politicians and beuracrats​), but it's not a universal solution to the "I don't want to tell you" scenario.

I think that the difference is that people are generally good at remembering the details that judges are normally interested in. People are notoriously bad at remembering passwords.

That's not something that's going to trouble US authorities given that the US invasion of Iraq was alleged to have been because the Iraqi leadership couldn't demonstrate that there were no "weapons of mass destruction" hidden somewhere in the country.