1. A system for modifying functions or available choices on a mobile device, said system comprising: one or more sensors, detectors, or antennas, said one or more sensors, detectors, or antennas determine relative or absolute position or coordinate of said mobile device; and a controller, said controller modifies functions or available choices on said mobile device; in case said one or more sensors, detectors, or antennas determine that said mobile device is within a range with predefined boundaries, then said controller receives a message indicating in-range status for said mobile device, and said controller modifies functions or available choices on said mobile device, according to one or more rules associated with said in-range status for said mobile device.