If you don't care for tools your employer furnishes (at least in a smaller company / non .gov environment), you don't care too much for the company, it would seem.
I don't think I'd dock him for replacing the ladder, but I would talk with him about his attitude. Maybe he had a brain fart, and forgot. Maybe he just doesn't understand that actions (and, in this case inactions) have consequences. Whether or not that ability will develop or is genetically supressed isn't a determination we can make over the web...
