[godshatter]

What assumptions does it make? What if one of those assumptions fails? For example, what if it's never called with a certain combination of parameters because nothing generated them until a new process was added somewhere else and that combination of parameters now cause it to fail? What if the format of a parameter changes slightly and it fails on that?

We have code like this where I work and cases where a change to something has caused that one rock solid process written by an intern in 1998 that few people even remember exists to suddenly start to fail. I would call it a ticking time bomb, and if it's one that will explode in a big way, it might be worth analyzing it to see how it will react to non-obvious parameters or environments.