>Why didn't you put two locks on your door? Clearly you deserved to get burgled if you only used one.

I can reasonably test that the bolt is in a locked position every time I close the door and turn handle on the lock. But a single remote sensor could have malfunctioned or simply be out of calibration a few degrees.

If the actual temperature at the airport is important to any set of users enough so that the difference between it being 18 or 22 deg C is relevant, one should expect that there be at least 3 sensors (much like clocks) and assuming variances between the 3 sensors are within tolerance an average of the 3 temperatures is taken.