Aluminess suggested to me that a good tight fitting pin will help strengthen the whole structure. I'm using a hitch pin with a lanyard on it and feel comfortable with it. Only once did the gate swing open...after the car wash it didn't get fully closed
. I try not to use a pad lock. It could get crude into it making it difficult to get off. Most people don't even know how to get them open anyway. But parked somewhere a lock might be a very good idea