Although no testimony will be taken at a prehearing conference, nevertheless, the claimant, carrier's representative, and any other witnesses in attendance must, if called upon by the prehearing examiner or the adverse party, fully participate by responding to requests for information reasonably necessary in the evaluation or defense of the claim presented. A violation of this rule by claimant may result in a continuance of the prehearing conference until a subsequent date, and a violation of the rule by any other party or witness may result in appropriate sanctions by the board.