I have been towing boat trailers and utility trailers with ball hitches for over 50 years. Relatively recent with travel trailers...only 5 years.
Typical ball hitches have a lifting lever that you lift up when lowering the coupler on the ball. The lever will only latch in place when the ball is correctly attached. And for 50 years I thought that was the entire procedure.
Nobody ever told me about the drill through hole in the lifting lever that is made to insert a latching pin.
On my travel trailer it looks like this:
With the latch pin in place, it looks like this:
The latch pin cannot be inserted in the coupler if the ball hitch is not fully engaged.
A locking pin is available for about $10.
Here is a pic of my boat trailer hitch with locking latch pin.
Nobody ever told me about the locking pin feature of these couplers. When I picked up my travel trailer at the dealer, they hitched it up for me, safety chains, trailer plug, ball hitch, but they never had a latch pin for the ball hitch.
I found out about this feature from a fellow member of a travel trailer camping group that I belong to.
I've been towing trailers thousands of miles without latching the coupler release lever. Lucky for me they never opened while trailering.
I know you have to have safety chains on ball hitch trailers.
But what about latch pins on the coupler release lever? Is it optional?
Now that I know what that hole is for, you can be sure I will use a latch pin or a locking latch bar when trailering.