An occupancy sensor is provided for detecting the occupancy status of a wheeled mobility device securement system. The occupancy sensor may additionally confirm adequate “tightness” of the wheeled mobility device securement system and/or provide an indication of the magnitude of “tightness.” In one embodiment, the occupancy sensor comprises a spring-loaded follower that breaks the straight-line path of a wheeled mobility device tie down as it travels between two touch points. The follower is displaceable from an extended position to a compressed position in response to the magnitude of tension applied to the tie down. Proximity sensors are used to detect the displacement distance of the follower, thereby providing an indication of occupancy, adequate securement, and/or the magnitude of tension.