I have painted the jaws (white) on my hitch. Makes it much easier to visually check. But I also do a pull test whenever I hook up. I don't use a lock, but after reading some of these postings, I might start to use one. I do use a pin through the lever latch.
Something else to check, if you are concerned about these parking lot no goodnicks, is that the wiring plug is still connected. That could be dangerous - no brakes to the trailer. Also check breakaway cable.
Like previous poster, I have a checklist, which I follow, Only problems occur when I get interrupted. As they suggested, if that happens, start over.