A monitoring system for developing information data, for use in association with an opening that provides access for removal by a customer of articles stored in an article storage area. In one embodiment, the monitoring system includes a beam forming device adapted to be arranged about the perimeter of the opening so as to form at least one radiation beam that spans the opening. The radiation beam has a position with respect to the opening that is sufficient to detect manual removal by the customer of one or more of the articles from inside the article storage area, by the article and hand of the customer causing a temporary blockage of at least a portion of the radiation beam as the article and hand of the customer pass through the opening. A processing circuit coupled to the beam forming device senses the blockage of the radiation beam, and in response to the sensing, develops the information data.