Indicates whether a group allows double-booking of events in the group's calendar. When enabled, double-booking allows two events to be scheduled and displayed on the calendar at the same time.
For a Calendar resource, this attribute allows the resource to be booked for two events at the same time.
The icsDoublebooking attribute can have a value of 1, which allows double-booking, or 0, which prohibits double-booking.
For a group calendar, the default value is 1 (allow double-booking). For a Calendar resource, the default value is 0 (prohibit double-booking).