I have a hitch on the Fiberstream
that looks just like this hitch.
I din't even notice until someone else mentioned it but on mone there is a small hole on the other side from what you have pictured here that will accept a small padlock or locking clip of some kind.
Unlike all the other ones I had seen where the latch could be locked into place,this one has a small hole in the side of the couple otself,for lack of a picture.
Again I overlooked this at first until someone pointed it out.
Maybe yours is the same,at least it is worth a look.