Exactly as Caesium said. It really doesn't matter, just make sure you keep it similar on all machines. Even if the exact number generated doesn't matter, the fact that you actually went ahead and made the call does. It's probably more safe to use it than not to use it, since most code is probably going to be in the realm of "run on all machines" rather than the little bits of code that are run only on some of the machines. If you find code that is going to only run on one machine (such as if it's located somewhere within an if block that checks the getActivePlayer) then you should use a non-synchronous random number generator.
Caesium had a good idea for the Caesium mod, where if unsure about whether or not it's needed, use a sorenRandNum call, but do it early in the function, before you get into problems of possibly entering into computer-independent code such as if-blocks with getActivePlayer().