When this is enabled for Lync Server, users are assigned a static, unique conference ID that is used for all of their meetings. A user’s conference ID is persistent by default, but if a user has back-to-back meetings, it is beneficial to schedule the second meeting with a unique ID. End users can do this easily when creating a conference, and it helps to prevent attendees from the second meeting from joining the first meeting if it runs to the end of the time slot.