If my understanding of the IR controllers is correct, each controller and
receiver use a keycode to identify it to the appropriate counterpart. For
example, if controller 1 has an ID of 0x00343234 and controller 2 has an ID
of 0x007898989, they will not interfere because the receiver for the
controller only tunes into the IR code that it needs. I'm not sure if it is
numerical like this or if it uses a bandwidth signal but the two need to
synch up somehow. That's the only logical way it can function. Otherwise,
you would only be able to use one wireless controller at a time...