an article removal alarm system includes a base unit for generating an ultrasonic signal for transmission in the vicinity of the base unit . a remote unit accompanying an associated article includes a receiver for receiving the ultrasonic signal . a threshold detector provides a threshold signal upon failure of the receiver to receive the ultrasonic signal at predetermined strength . an alarm unit then generates an alarm signal in response to the threshold signal . in a particular implementation the system enables monitoring of the proximity of a stylus or other input utensil to a responsive user interface of an electronic device .