[Haskell-beginners] Why getArgs is in the IO monad

From: "John M. Dlugosz" (And that begs the question of why getArgs needs to be monadic in the first place. It doesn't change its value; it's a strict constant at run-time, and not knowing it at compile time is my problem how?)

Actually, the value of the arguments can be changed - at least on some platforms. They are writable from C, if nothing else. What should getArgs do if some ffi changes the arguments before it's called? Mike