sensor (required) — Indicates whether or not the geocoding request comes from a device with a location sensor. This value must be either true or false.
requests without it are denied:
"REQUEST_DENIED" indicates that your request was denied, generally because of lack of a sensor parameter.
Why is this? Why do they want to know so badly whether the request comes from a client with a sensor or not?
Is it for statistical reasons, or to be able to provide services in the future?