According to the ecobee manual, when Follow Me is enabled, if motion is detected in the cold room, the temperature reading from that sensor will be used by the ecobee to decide when to operate your heating or cooling system. If more than one sensor detects motion, the average of these sensors will be used. When Follow Me is disabled, the ecobee will continuously use the average temperature readings from all the sensors that you've selected as the desired temperature to control your thermostat.