Happy New Year all.
1. Several stage magicians who make use of "hypnotism" themselves cannot agree on what hypnotism actually is. What it isn't is some sort of altered mental state where your own conscious will is switched off and can be replaced by someone elses suggestion. All the evidence shows the subject has to be complicit and aware of what is going on.
2. Given that we don't fully understand what hypnotism actually is, and the fact that we cannot even design any objective empirical study to test its claims, how can we evaluate the alleged "truth" of any statements elicited from a subject whilst "hypnotised"?
3. Lie Detectors, or Polygraphs are not infallible - in fact most serious scientific study seem to show them as pseudoscience of limited to no value. Despite this, some Govt departments especially in the US use them - what no one anywhere does is to rely exclusively on evidence or statements derived from witnesses questioned using a polygraph - it adds to the totality of statements and evidence already collected.
4. You have been given the same answer from several people now - evidence presented in court under oath will never ever consist of "true" statements collected under hypnosis. End of story.