And if they are happy to lie at a heralds inquisition, why not lie at an inquisition post mortem, a bill of complaint, or frankpledge. People lie all the time in court, witnesses, barristers, judges, police, 'experts', and not the least the one on trial.
If folk think they stand to gain something, cash, credibility, position or whatever, they will mould the story to suit themselves. So at some point we have to have trust.