Abstract: A detection system for use by a checkout clerk in a checkout line to detect a load left on the lower tray of a shopping cart by the customer. The shopping cart has a lower tray pivotably mounted on a frame. The tray is movable between a first and second position when a load is placed on the tray. A field producing source such as a permanent magnet contained within a shield material is attached to the cart, and the field is actuated at a distance when the tray is moved from the first to the second position by displacing the magnet and the shield material. A detector for detecting the presence of that field as the shopping cart passes through the checkout line is coupled to a control circuit capable of signaling the checkout clerk that the load is on the lower tray.