Although implied shares can improve performance by not storing the same data multiple times, it has many negative impacts. For example, implied shares cause problems in Hyperion Planning at the load level (level 0). A parent with a storage property of Stored that has one child (or only one child that consolidates) will create an implied share. This results in level 0 members being locked, preventing web form data entry. In Essbase/Planning, the storage method of any parent with one child has to be changed to Never Share to allow user input.
For those of you who have been snake bitten by this, you will welcome a relatively unknown Essbase configuration setting in the Essbase configuration file (essbase.cfg).