When volume guarantees are in effect, a new FlexClone volume uses the Snapshot copy it shares with its parent to minimize its space requirements. If you delete the shared Snapshot copy, you might increase the space requirements of the FlexClone volume.
For example, suppose that you have a 100-MB FlexVol volume that has a volume guarantee of volume, with 70 MB used and 30 MB free, and you use that FlexVol volume as a parent volume for a new FlexClone volume. The new FlexClone volume has an initial volume guarantee of volume, but it does not require a full 100 MB of space from the aggregate, as it would if you had copied the volume. Instead, the aggregate needs to allocate only 30 MB (100 MB – 70 MB) of free space to the clone.
Now, suppose that you delete the shared Snapshot copy from the FlexClone volume. The FlexClone volume can no longer optimize its space requirements, and the full 100 MB is required from the containing aggregate.