The locking latch was a safety recall done way back in the mid '70s. The government said in a collision, there was a possibility of the rider hitting the standard latch with their knee, chest etc. and cause the cap to open, spilling fuel and causing a fire. I always thought they were hard enough to open on purpose, let along by accident. I remember sitting in the alley of the Honda dealership I worked at then, in shorts and t-shirt, doing one, after another, after another, all day, for weeks, doing every model with that style cap.