Happened to us last June..getting ready to break camp one morning and was hitching up our Casita 17' w its anti-sway bar thingie. I always do a walkabout b4 rolling and check the hitch "one more time." This time as I reached for the lock end of the hitch bar pin, the whole lock end came off in my hand..I looked inside and there were a buncha busted little plastic parts and broken metal. Fortunately I carry at least one spare hitch pin w a spare cotter pin..I took off the broken one and slipped in a new one..no lock but it was a new pin. Whew..bks if that "lock" had fallen off on the road, the picn could have easily dropped out and the whole ball-mount and bar could have just slid off. Maybe the chains wd have held..maybe.
Here is an example of what broke( only had 8 months duty)
https://www.walmart.com/ip/Reese-703...in-D/167021339