such a witnesses's account will have no effect on the case/trial.
Thats not what you say. Ask them to define the meaning of truth, then ask how you can know truth when in fact, all you know is your perception. How can they trust your perception as truth? And if they cant, why do they bother asking you that question? Lead them in an infinite loop where they contradict themselves. ie: How can you expect of me to answer truthfully if the question is biased or attempts to cover up a truth? For true truth to come out, mustn't both parties be binded to the obligation of telling the truth? If not I could truthfully answer a misguided question not out of lack of knowledge, but lack of understanding...<br />
Then when questions start, you say, hmm, truth is I dont really remember much of the details. Give the vaguest desc<x>ription possible. Annnndddd thats the truth. Oh and you dont fully understand the intentions behind the question and thus cannot truthfully answer.
held in contempt?..
held in custody until you toe the line...or fined if your testomony isn't all that important