PART III - FORMS OF MUTUAL ASSISTANCE
6. Procedure for an evidence-gathering order or a search warrant
(8) (a) Where a person refuses to answer a question or to produce a document or article pursuant to subsection (7)(b) or (c), the Central Authority shall notify the foreign State and request the foreign State to provide a written statement on whether the person’s refusal was well-founded under the law of the foreign State.
Obligation to inform the Court of reasons for denial of assistance
EDIT.