Here I posted an answer on how to disable mouse and keyboard input using
xinput, with the presumption that if the question is about UNIX, X specific answers are good. However, turns out, the OP was interested in doing that on OS X, whose GUI has nothing to do with X.
So, if a question is OS X GUI based, does it belong here? When can we say "ask that on Apple"?
Here is a closely related question, but the above point wasn't clearly resolved, so I'm following Gilles' suggestion to raise it here.