(b) Request for appearance. The probable cause panel may request the appearance of the party or parties being investigated in cases involving the review of plans and specifications, as well, as in those cases in which, because of their complexity or significant public policy considerations, such an appearance would assist the panel in their deliberations. A party requested to appear is not under obligation to do so, and such non-appearance shall not prevent the submission of written responses or documentation to the panel nor shall it preclude the panel from proceeding with its deliberation.