The Maryland-National Capital Park and Planning Commission may raise the defense of partial governmental immunity for any liability exposure: In excess of insurance limits; If punitive damages are sought; or For any other liability exposure not covered by insurance. Nothing in this section may be construed to be a waiver of the Maryland-National Capital Park and Planning Commission’s total governmental immunity. This section is intended to include all claims pending on June 1, 1978, provided that an insurance policy to cover such liability was in effect at the time the claim accrued.