To use the occupancy feature of remote sensors, enable the "Remote Sensor Occupancy" setting.
This setting is located in Home Settings->System Settings.
When enabled, Flair will use the occupancy readings from remote sensors to set rooms to active or inactive. Remote sensor occupancy status can be interrupted by a schedule event or by toggling the Active switch on a room.
When disabled, Flair will not use occupancy readings from remote sensors. Active state will be determined by the Home/Away Mode.