The recourse when nobody can be found who knows or remembers why the fence is there, is to figure it out based on first principles. It's fine to do "tear it down and see what happens" as a consciously chosen trade-off for expediency. But in my experience people often act like there's just no way of knowing if you can't find someone to ask, and that's very rarely the case.
In software, sure, reasoning from first principles is likely to work. With older traditions, it could just as easily lead you to just-so stories and other false explanations, such as the endless number of false etymologies which make all seasoned linguists deeply suspicious of any cute etymology, especially one which could be used to make a point.
