These are two distinctly different circumstances and the ramifications are very different.
Signs with exceptions or qualifications - As noted above, if a dean or department head signs the fiscal closing certification letter, subject to certain specific exceptions or qualifications, it is the responsibility of the Campus Controller and Vice Chancellor of Administration to evaluate the nature of the exception in order to determine the overall effect on the integrity of the fiscal closing process, the accuracy of the reported financial information contained in the general
ledger or the adequacy of disclosures associated with the preparation of the University's financial statements.
After a discussion with the dean or department head to ensure proper understanding of the exception, the evaluation may result in a conclusion that no additional audit work is required. On the other hand, the exception may result in a decision to expand the scope of audit work performed in a particular area. The additional procedures may be undertaken by department staff, controller's staff, internal audit staff or the external auditor.
Refusal to sign - If a dean or department head refuses to sign the fiscal closing certification letter, the Campus Controller and Vice Chancellor of Administration must evaluate this lack of response and presume the underlying rationale is indicative of systemic exception in the specific school/college/ administrative department or unit.
After a discussion with the dean or department head, the evaluation may result in a conclusion that no additional audit work is required. On the other hand, the conclusion may be to expand the scope of audit work performed in a particular area. The additional procedures may be undertaken by department staff, controller's staff, internal audit staff or the external auditor.
The lack of a response should be brought to the Chancellor's attention. The "tone at the top" set by campus management is obviously extremely important in terms of exhibiting the appropriate leadership in the areas of responsibility and accountability.
See, University of California Statement of Ethical Values and Standards of Ethical Conduct at
https://www.ucop.edu/ethics-compliance-audit-services/_files/stmt-stds-ethics.pdf