The older help files had verbiage to that effect. But I'm not finding it in the current help file.
However, creating a personal calendar in the system would be a bad idea. First, no calendar is truly private. A admin for that unit could add themselves to that calendar. Secondly, all calendars are attached to units, not individuals. If they move out of the unit, then they no longer can see or edit their calendar.
The only way to know if this is appropriate use of the calendar is to see if it's being used for church purposes. It might be a Bishop appointment calendar and the only reason that it hasn't been shared with the bishop is because he'd never use it. Or it might be a test calendar so that that person could experiment with how the calendar works without messing up anyone else.
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